A Plain Language Guide

GrowingFresh MarketSalad Greens

A. C. Newenhouse

�The Wisconsin Farm Center has more informationabout services to help beginning farmers. To find this information on the internet look under the heading Farming and Agriculture athttp://datcp.state.wi.us/.

Your local county Extension office also has moreinformation for fresh market farmers. Go to http://www.csrees.usda.gov/Extension/. Click on your state and then your county to findthe Extension office near you.

Plant Description ..............................................................................2

Lettuce ......................................................................................................................2Spinach ....................................................................................................................2Swiss chard ..............................................................................................................3Asian greens ............................................................................................................3Specialty greens ......................................................................................................3Site selection ............................................................................................................3

Variety Selection................................................................................4

Table A. - Lettuce varieties ........................................................................................4Lettuce varieties ......................................................................................................5

Planting and Care ..............................................................................6

Soil preparation ........................................................................................................6Raised beds ..............................................................................................................7Seeding ....................................................................................................................7Starting seeds ..........................................................................................................8Planting lettuce ........................................................................................................8Plant spacing ............................................................................................................8Planting spinach ......................................................................................................9Planting Swiss chard ..............................................................................................10Planting Asian greens ............................................................................................10Table B. Planting guide ..........................................................................................11Season extenders ..................................................................................................12Frost dates maps ....................................................................................................12

Soils and Nutrient Management ....................................................14

Table C. - Soils and Nutrients..................................................................................14Soil pH ....................................................................................................................15Fertilizer needs ......................................................................................................15

Irrigation ..........................................................................................15

Harvest, Handling, and Storage......................................................16

Preventing Stress on Your Body ....................................................19

Weed Management ..........................................................................20

Pest and Disease Management........................................................21

Contents

1

Most salad greens grown in theMidwest are leafy annuals that likecool weather, but some varieties cangrow in summer heat. Many growersoffer salad greens or leafy greensearly in the growing season and againin the fall. Salad greens grow well inan unheated plastic greenhouse orhoophouse.

Salad greens spoil quickly so locallygrown fresh greens are usually thebest quality. You can sell leafy greensfor a high price if you grow andmarket them well, but you may needto use a lot of hand labor. Salad mix isa collection of leafy greens soldtogether in a bag. Customers likesalad mix because it is convenient.You can grow the greens as a mixturein the field or put them together afterharvest. Salad greens are veryhealthy.

Plant Description

Lettuce

Lettuce (Lactuca sativa) is in the asterfamily, native to the easternMediterranean and Asia Minor. Eventhough lettuce is low in vitamins andnutrients, it is an important crop in theUS because people eat a lot of it.Lettuce in your diet gives you fiber,vitamins A and C, calcium, and iron.Loose leaf lettuce has more nutrientsthan head lettuce, and dark greenleaves have more nutrients than lightcolored leaves.

Lettuce varieties come in many colorsand leaf shapes.

Spinach

Spinach (Spinacia oleracea) is nativeto Iran and is in the goosefoot familysimilar to lambsquarter(Chenopodium). Spinach is an annualthat can grow in colder weather thanlettuce. It contains vitamins A and C,calcium, phosphorus, iron, andpotassium. Spinach also has a lot offiber and some protein. Spinachplants grow with many leavesattached to a very short stem. Leavescan be smooth or crinkled.

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Swiss chard

Swiss chard (Beta vulgaris var. cicla)is native to the Mediterranean and isin the goosefoot family similar tolambsquarter (Chenopodium). It is avariety of beet (Beta vulgaris) whichgrows large leaves while the rootstays small. Swiss chard tastes likespinach and has crinkled leaves andfleshy leaf stalks. Chard keeps itshigh quality even in heat and does notproduce a premature seed stalk.Therefore it is often grown in thesummer in the Midwest.

Asian greens

Many greens that are common in Asiaare also sold as salad greens in theU.S. Many of these greens are relatedto cabbage or mustards (Brassica)such as mizuna, tat soi, komatsuna,pac choi, hong vit, and hon tsai tai.They are easy to grow and like coolweather. Asian greens have a lot ofvitamins.

Specialty greens

Many other crops are grown as saladgreens in the Midwest. Some of theseinclude arugula (Eruca sativa),cilantro (Coriandrum sativium), cress(Lepidium sativum), mâche(Valerianella locusta), miner’s lettuceor claytonia (Claytonia perfoliata),dandelion (Taraxacum officinale), kale(Brassica oleracea and Brassicanapus pabularia), collards (Brassicaoleracea), orache (Atriplex hortensis),purslane (Portulaca oleracea), NewZealand spinach (Tetragoniatetragonioides), amaranth

(Amaranthus tricolor) and sorrel(Rumex acetosa). New Zealandspinach and purslane grow well in hotsummer weather. Miners lettuce andcress tolerate cold and can extend thegrowing season. Small amounts ofarugula, cilantro, mizuna, anddandelion are used to add flavor tosalad mix.

Site selection

The small seeds of leafy greens likerich, fluffy soil high in organic matter.Choose a site where the soil warmsup quickly in spring. Leafy greenshave shallow root systems and lose alot of water through their leaves, soplant them on soil that holds moisture.Be sure the soil drains well becausethat will help prevent diseases. Youcan plant early season crops onsandy soils which warm up quickly.Plant mid- to late-season crops onheavier soils or soils with high organicmatter so they hold moisture. Thesmall seeds to leafy greens cannotgerminate in crusted soil. To preventa soil crust use shallow cultivation,mulch, and only give the seed bedenough water to wet the soil atgermination but not to drench it.

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Variety Selection

Choose varieties of leafy greens that suit market gardening in the Midwest. Look forvarieties that resist disease, tolerate heat, have good flavor, and have differentcolors, shapes, and textures. Plants that cannot take heat will send up an early seedstalk, which is called bolting. Leaves from plants that have bolted do not taste good.

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Lettuce varieties for the Midwest

LeafButterhead (Boston and Bibb)

Romaine Crisphead Spinach Chard

Black SeededSimpson

Barbados Coastal Star Crispino SpaceBrightLights

Grand Rapids Buttercrunch Freckles Great Lakes TyeeFordhookGiant

Great Lakes Cherokee Green Forest Rhubarb

Tropicana ConceptParris IslandCos 714

New Red Fire Nancy

Oakleaf types,Red and Green

Nevada

Red Sails Mottistone

Red Salad Bowl Red Cross

Vulcan Rex (for greenhouse)

Royal Oakleaf Sylvesta

Waldmann’s Teide

Table A. - Lettuce varieties

Lettuce varieties

There are four main types of lettucecommonly grown in the Midwest:crisphead, butterhead, romaine, andleaf (table A).

Crisphead varieties (Lactuca sativavar. capitata) are often called“iceberg” lettuce. Plants start withmany leaves on a very short stemand then leaves begin to overlap eachother and become tightly folded toform a dense head which is usuallymore than 6” across. Leaves arelarge, heavy, and brittle. The outerleaves are green and the inner leavesare white or yellow.

Butterhead lettuce varieties formsmaller more compact heads thancrisphead. Leaves are looselycrumpled and have thick veins andmidribs. Butterhead lettuce has moreflavor and a buttery texture comparedto crisphead lettuce. There are twotypes of butterhead lettuce: Boston—a variety which produces large headswith light green leaves and can growin midsummer, and bibb—a smaller,dark green variety for spring or fall.Bibb lettuces do not ship well sincetheir leaves bruise and tear easily, sothese types are good to grow for localmarkets.

Romaine is also known as cos(Lactuca sativa var. longifolia).Romaine lettuce forms long uprightheads with long leaves that have thickmidribs. Romaine lettuce has coarseouter leaves and tender, flavorfulinner leaves. It tolerates changes in

temperature and moisture better thancrisphead or bibb lettuce.

Leaf lettuce (Lactuca sativa var.crispa) varieties come in all types ofshapes, colors, and textures whichchefs and consumers like. They areparticularly good to grow for localmarkets since they do not ship welland are not usually available fromother states.

When you choose spinach varieties,look for ones that resist diseases,resist bolting, and are high in nutrition.Spinach varieties have either smoothleaves or crinkled (savoy).

Swiss chard varieties should also bedisease resistant and can be differentcolors such as red, pink, orange,white, yellow, and green.

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Planting and Care

Refer to table B for the amount ofseed you will need, how deep to plantseed, how far apart to plant, when toplant, days to first harvest, and yield.

Leafy greens or salad greens areready for market quickly and farmersusually plant seeds every few weeksso they can sell lettuce all season. Inthe winter, make a calendar that liststhe dates you plan to plant saladgreens, since it can be hectic duringthe growing season to keep up withso many plantings. Plant seed assoon as possible in the spring. Youcan grow spinach, asian greens, andsome other cold tolerant crops in latefall and winter under shelter such asfloating row covers, a cold frame, or ina hoophouse with 1-2 layers of clearplastic. See the section on seasonextenders to learn more.

If you plant heat sensitive leafy cropsin summer, you should pre-germinateseeds by soaking them in water untilthe first root just begins to form. Thisis because warm soil prevents seedgermination. Change the water dailyto give the seeds oxygen, or placethem on a paper towel, roll up thetowel, and keep it moist until the firstroot emerges. Then plant the seed byhand.

You can try to cool the crop byshading plants with a lightweightfloating row cover (which lets lightpass through) or by planting betweenrows of taller crops planted north tosouth.

Soil preparation

Work beds 6-7 inches deep topromote good rooting. Just before youplant, cultivate the soil lightly toprevent a crust. If erosion is not a

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problem, prepare the soil in fall toplant in early spring. Cold wet soil inspring might delay planting. Neverwork wet soil because this can causesoil compaction. Compacted soilsprevent oxygen and water fromreaching roots, and plants do notgrow as well or produce as much.

Raised beds

You can pile up soil to make raisedbeds to improve soil drainage andprevent compaction. Raised beds areusually 4-5 feet wide and 100 feetlong. Leave a 1-foot aisle on eitherside of each bed for a path.

Seeding

Plant seeds by hand or with a seeder.After planting, give the seed bedwater regularly until germination sothe soil does not form a crust. Seedsfor salad crops are often very small,and plants need to be thinned out togive them space to grow. Somecompanies sell pelleted seeds thatare coated and rolled to make themuniform and easier to handle,especially for growers who plant witha precision seeder. If you are anorganic grower, check to make surethat the coating on pelleted seed isorganic, because some pelletedseeds have pesticides in the coating.Precision seeding is done with specialplanters and uniformly sized seeds,and is done in a way that you do nothave to go back and thin the plants.Many different types of planters areavailable such as the gravity-feedcone seeder, belt-drive seeder,vacuum seeder, and walk-behindplate-type seeder. Some growers whodo not use precision seeders thinsalad greens by hand and sell thesmall plants that they remove fromthe rows.

If you have seeds left at the end ofthe year store them in an airtightglass jar in a cool, dark, dry placesuch as a cellar. You can sprout theseeds to test germination next year,or sprout them to sell as fresh leafysprouts. In the best storage theseseeds could keep for 2-3 years.

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Starting seeds

You can start leafy greens in thegreenhouse and transplant themoutdoors to get an earlier crop. Startyour transplants 3-4 weeks earlierthan you will plant them outdoors. Youcan buy or mix your own sterilepotting mix. The mix should includecompost, peat, or sphagnum to holdmoisture; vermiculite or perlite foraeration; and mineral and nutrientsources to feed the new plants afterthe first roots form.1. Fill plastic or styrofoam cell trays

with potting soil, or make individualblocks with a soil blocker. Cells assmall as 1inch diameter are fine.

2. Barely cover the seeds with asmall amount of soil, since theyneed light to germinate.

3. Label the trays with variety andplanting date.

4. Keep soil moist but not wet.

5. The temperature at night should be10-15 °F cooler than during theday.

6. Thin seedlings to one plant per cellor plug, or one plant every inch.

7. Ten days before transplanting outto the field, harden off the plantsby putting them outside for a fewhours each day during thewarmest time of the day, or moveplants into a cold frame. Thesection on season extensiondescribes a cold frame.

Planting lettuce

Lettuce prefers weather between65°F and 70°F during the day and45°F and 55°F at night. Somevarieties of lettuce grow better underlong days while for others day lengthdoes not matter (they are “day-neutral”). If lettuce gets too hot underthe long days of summer it canproduce an early seed stalk (“bolt”)and poor flavor. You can plant lettuce,like most salad greens, as early asApril 15 in southern Wisconsin. Plantmore every 2-3 weeks as long asthere is cool weather. You can plantsome varieties that tolerate heat aslate as early July. Under the bestconditions, lettuce seed will germinatein 2-4 days and come up shortly after.If the soil is cooler, then germinationis slower; and if the soil is warmer(above 77°F) then germination stops.

Plant spacing

✤ For head lettuce, plant 3 seedsevery 8 inches in rows 12-18inches apart.

✤ Thin head lettuce to 1 plant every8 inches.

✤ For leaf lettuce, plant either in rows2-4 inches wide or in beds.

✤ Plant leaf lettuce close togetherand thin to 1-2 inches betweenplants.

Decide whether you want to combineseeds to mix varieties within theplanting beds or grow themseparately and mix leaves togetherafter harvest. Since these seeds needlight to germinate you should barely

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cover the seeds with a small amountof soil when you plant them. Sprinklelightly with water to give the plantseven moisture.

You can start head lettuce from seedindoors and transplant it out in earlyMay. Water transplants well atplanting.

Planting spinach

Spinach grows best at 55-65°F. In theMidwest, grow spinach in the springor fall. Plant spinach from mid Aprilthrough early May and again in earlyAugust through early September. Ifyou plant in the heat of summer, longdays and warm temperature causesspinach to send up an early seedstalk (to bolt) and stop making largeleaves. Spinach is very hardy. If theplant is used to cold it can take somefreezing down to 14-20°F.

You can plant spinach in late fall theyear before and plants will either growto maturity before frost or grow bigenough (3-4” diameter) to survive the

winter. Early the next spring they willbegin to grow new leaves. If you plantspinach seeds in late fall or earlywinter and cover them with mulchthey might sprout early the nextspring.

✤ Plant in rows or in beds.

✤ For salad mix, plant seeds ¾ inchapart in rows 2-4 inches wide.

✤ For full sized leaves, plant 1¼ inches apart in rows 12-18inches apart.

✤ For salad mix, clip leaves whenthey are small.

✤ For full sized leaves, pick outerleaves first.

Seed should be planted ½ inch -¾inch deep. In cool weather, between40-45°F, almost all of the seeds willgerminate but will take up to 3 weeksto come up. In warmer weather,germination is faster (7-10 days) butthe percent of seeds that germinategoes down.

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Planting Swiss chard

You can plant chard as early as mid-April and then every four weeks. If yougrow it for salad mix pick it until 30days before frost. If you grow it for fullsized leaves pick it until 60 daysbefore frost. Cold weather can causebolting, an early seed stalk, whichstops leaf growth and makes leavesbitter. Plant either in the field or usetransplants.

✤ For salad mix, seed ½ inch deep inthe same spacing as for leaflettuce.

✤ For full sized leaves, space plants8-12 inches apart in the row.

✤ For salad mix, clip leaves whenthey are small.

✤ For full sized leaves, pick outerleaves first.

Planting Asian greens

Plant Asian greens when the weatheris cool, in spring and fall. If you plantin the heat of summer, Asian greenswill start to flower and the leaf flavorwill be bitter.

✤ For salad mix, plant seeds closertogether.

✤ For full sized bunches, plant seeds¼ inch deep and 2 inches apart inrows 18 inches apart.

✤ For salad mix, clip leaves whenthey are small.

✤ For full sized leaves, pick outerleaves first.

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Table B. Planting guide

a Plant about 1 week later along the lower lake shore and in the central part of the state and about 2weeks later in the north.

b If you use a plate-type seeder, the plate will make the spacing between plants.c Varieties are ready to harvest at different times; plant again and again to have a longer growingseason.

d Estimated yields under less than ideal growing conditions; actual yields will depend on weather, soilfertility and cultural practices.

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Planting time inSouthern WIa

Plantsor seedsneeded

for 100 ftof row

Seeddepth

(inches) Spacing (inches)b

Days tofirst

harvestc

Estimatedyield

(lb/ft ofrow)d

Vegetable Indoors OutdoorsBetween

rowsBetween

plants

Lettuce,head

March 15 May 1 100 plants - 15-18 8-10 60-75 0.50

Lettuce,leaf

- April 15 ¼ oz ¼ 15-18 2-3 40-60 0.25

Spinach - April 15 1 oz ¾-1 15-18 1-2 40-60 1.00

Chard - April 15 1-1¼ oz ½ 15-18 12 40-50 2.00

AsianGreens

- April 15 1/6 oz ¼ 15-18 2-6 35-45 0.25-0.50

Season extenders

You can make the growing seasonlonger by protecting plants from latespring frosts and early fall frosts usingthese methods.

Floating row covers. Floating rowcovers are special sheets of whitefabric made of spun-bondedpolypropylene which lets sunlight andwater through the fabric but stopsinsects.

✤ You can use row covers to protectplants from frost, wind, andinsects.

✤ Row covers come in differentweights and the thicker ones canwarm plants by 4-8°F.

✤ You can plant salad greens 3-4weeks earlier in the spring andharvest 3-4 weeks later in the fall.

✤ You can wash and re-use rowcovers for two to three seasons.

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April 26 - May 2

May 3 - 9

May 10 - 16

May 17 - 23

May 24 - 30

May 31- June 6

September 13 - 19

September 20 - 26

September 27 - October 3

October 4 - 10

October 11-17

October 18 - 24

Frost dates maps

Last spring killing frost First fall killing frost

Put the row cover on top of the cropor hold it up with wire hoops. If youuse wire hoops to hold up the rowcover, use 9-gauge wire 6 feet apartand buried 1foot deep on each side ofthe row.

If you gather the edges and looselybury them along the crop row, then asthe crop grows it will push up enoughfabric to form a “floating” cover. Youcan also use rocks or heavy posts tohold down the edges. If you want therow cover to keep out insects youmust seal all the edges tightly to theground. If you use row covers forearly spring or late fall crops, takethem off when the air is warm enoughfor the crop to grow. Before this, letthe plants harden off for a few days toprevent heat and sun from burningthe crops. Do this by removing coverson cloudy days or for a few hours onsunny days. On very hot days, besure to lift the row cover to give plantssome air.

Tunnels and cold frames. Tunnelsare large, unheated plastic hoop-frames that can also be used tolengthen the growing season. Usemetal or plastic hoops to hold up clearplastic over the crop. Cut slits in theplastic for air flow. Tunnels made ofclear plastic with slits increasedaytime temperatures by 10-30°F andgive 1-4°F of frost protection.

Cold frames are a type of plantingbed made by building wooden sideson each side of a bed on the ground.The back is higher than the front and

the frame holds up a glass top at anangle to the sun facing south. You canuse an old window to make a coldframe. Cold frames also warm the soiland let you grow crops earlier in thespring and later in the fall.

Greenhouse production. Saladgreens grow well in greenhouses orplastic hoop houses, where you canplant 4-6 weeks earlier than outside.You can also plant through Novemberbefore sunlight is too weak. You canuse floating row covers on top ofcrops in a greenhouse or hoop houseto give extra warmth.

Be careful to control nitrate levelswhen you grow salad greens inside inlow light, especially spinach. Nitratecan build up in these plants and formnitrite which is toxic to people. Keepleaf nitrate levels down by using theleast amount of nitrogen fertilizer andputting it just along the plants insteadof over the whole area. Give plantsmany small amounts of fertilizerthrough the growing season insteadof one large amount.

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Soils and Nutrient

Management

Get a soil test before you plant a fieldfor the first time and then at leastonce every 3 years. For informationon how to collect samples and whereto send them for analysis, seeUniversity of Wisconsin Extensionpublication Sampling Soils for Testing(A2100).

Most soil tests include pH, organicmatter, phosphorus, and potassium.You can also ask to test for nitrate-nitrogen, calcium, magnesium, sulfur,boron, manganese, and zinc. You willreceive the results of your soil testalong with fertilizer recommendationsbased on how you will use your field.You can also test your potting soil andthe soil inside your hoophouse orgreenhouse.

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Annual nitrogen, phosphate, and potash for salad greens

Nitrogen Phosphate and potash

Organicmatter

Amount to applyaAmount to applya

Phosphate (P2O5) Potash (K2O)

Vegetable % lb/a oz/100 sq ftSoil testcategories

lb/a oz/100 sq ft lb/a oz/100 sq ft

AsianGreensb <2.0 145 5.4 _

Heavy feeder, more than lettuces2.0-9.9 120 4.4 _

10.0-20.0 95 3.5 _

>20.0 50 1.9 _

Lettuceand SwissChard

<2.0 120 4.4 optimum 40 1.5 160 5.9

2.0-9.9 100 3.7 high 20 0.7 80 2.9

10.0-20.0 80 2.9 very high _ _ 40 1.5

>20.0 40 1.5 _ _ _ _ _

Spinachc <2.0 100 3.7 optimum 20 0.7 50 1.8

2.0-9.9 80 2.9 high 10 0.4 25 0.9

10.0-20.0 60 2.2 very high _ _ 10 0.4

>20.0 30 1.1 _ _ _ _ _

Table C. - Soils and Nutrients

a Follow guidelines from your soil test.b Pak choi used as example.c If you grow spinach with lettuce or chard, follow guidelines for lettuce.

Soil pH

Soil pH measures acidity and shouldbe between 6.0 - 8.0 for salad greensso they can take up the most nutrientsfrom the soil and have enoughminerals. If they don’t have enoughminerals plants can turn yellow, formbrown spots on leaves, or otherproblems. For lettuce, pH 6.0-8.0 isbest and less than 5.5 is too acidic;for spinach, 6.0-7.5 is best, and forchard 6.5-7.5. If the pH is below 6.0,apply aglime to raise the pH.

Fertilizer needs

Leafy greens need nitrogen,phosphorus, and potassium in largeamounts and many other nutrients insmall amounts. Leafy greens have ashallow small root system, so theyneed small amounts of fertilizer often.Also, this schedule gives fast steadygrowth for crisp high quality leaves.Nitrogen is the most importantnutrient for leafy greens. Put down nomore than half the amount of nitrogenyou need during the growing seasonwhen you make the field ready forplanting. Later, such as when you thinthe plants, put down more.

Table C gives the amount of fertilizerthese plants need. When you give theplants fertilizer later in the season, putit in a strip near the plant roots. Givethe plants more nitrogen in the lastfew weeks before harvest, becausemost of the plant’s growth happens atthat time.

Choose fertilizer from organic orinorganic sources. Healthy soil has

tiny organisms (microbes) that breakdown organic matter into nutrientsthat plants need to grow. Over time,organic fertilizer can build your soiland make the soil more healthy andfluffy which lets plants grow moreeasily.

Inorganic fertilizers give plantsnutrients quickly but do not build thesoil. Some inorganic fertilizers have alot of salt which is bad for soilorganisms. Organic fertilizers cancome from manure, compost, fishmeal, bone meal, and live composttea that includes oxygen. Recentstudies show that live compost teahelps prevent plant diseases and alsogives nutrients to plants. Livecompost tea is made by carefullymixing fungi, bacteria, sugars, water,and a steady stream of air to growactive soil micro organisms.

Irrigation

Salad greens need water regularlybecause they have big leaves and asmall shallow root system. Beforegermination, water the soil so a crustdoes not form. As plants grow, noticeif leaves wilt in the middle of the day.If so, they need water. Plants that wiltfor a short time will not produce as biga yield. Plants that wilt often or for along time might die.

Use either drip irrigation or sprinkler.Drip irrigation saves water and helpsprevent leaf diseases. Prevent tipburn(see page 22) with frequent watering.Mulch can help keep moisture in thesoil.

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Harvest, Handling,

and Storage

Most people pick salad greens byhand in the Midwest. Growers eitherpick and sell the outer, older leavesfrom each plant or cut all the leaves atonce. Either way, plants grow newleaves and you can get manyharvests from each planting.

Taste your own crop to learn the besttime to harvest from your field. If youknow your own crop well you can talkabout the high quality of your producewith customers. Most salad greenscan be cut when they are young andon to a point where they begin to losetheir flavor. Some salad greens turnbitter if you harvest too late. Also,plants harvested late tend to get morediseases. Some growers sell “micro”

greens: tiny leaves picked when thefirst true leaves appear.

If you cut bunches of leaves or heads,use a sharp knife or scissors. Cutheads below the lowest leaf. Removethe outer leaves and any other leavesthat don’t look good. Take a mesh bagsuch as you use for laundry and use itto line the harvest container. Pickleafy greens into the mesh bag tosave time later.

Leafy greens stay fresh and crisp ifyou cool them quickly and keep themin high humidity. ✤ Put the bagful of greens in a cool

water bath for a few minutes rightafter harvest.

✤ If the leaves are dirty, change thewater once or twice.

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Buy or make washtubs. You can useplastic food barrels cut in half the longway. Build a wooden framework tohold the washtubs at a good heightfor work. Cut a hole in the short endto put in a plastic (PVC) pipe elbowand valve (from the plumbing sectionof your hardware store). Put this pipeinto a long plastic (PVC) pipe to drainthe water away from your workstation. Or choose a bigger tank towash greens, such as an old stainlesssteel bulk milk tank from a dairy farm.Some growers use a jacuzzi-spa typeof motor for a bulk milk tank to makea bubble-type washing system forsalad greens.

Dry greens by spinning them for a fewminutes or laying them out on screentables.

✤ You can spin dry a small amount ofwashed greens by swinging themesh bag in wide circles over yourhead.

✤ Some growers use a small tabletopsalad spinner that you crank byhand.

✤ If you have larger amounts to dryyou can build a spinner from anold washing machine. Put twobags of greens into the washingmachine and set it to “spin cycle”for a few minutes.

✤ You can also use a restaurantsalad spinner with an electricmotor to spin dry a lot of greens.

Pack greens into waxed cardboardboxes and store them in a cooler. ✤ Line the box with a clean damp

cloth to keep humidity high.

✤ Do not let the temperature fallbelow 32°F. See below for storagedetails about each crop.

✤ Do not store apples, melons, ortomatoes in the same cooler asgreens because those crops giveoff a gas as they ripen (ethylene).This gas makes leafy greens turnyellow.

Sell greens bulk by the pound or inplastic produce bags as soon as youcan after harvest. You can keepgreens in a cooler for 1-2 weeks.

Details about Harvest and Storagefor Each Type of Salad Greens

Butterhead lettuce is mature andready 42-70 days after planting. Theexact length of time depends onweather and the variety you grow.Leaf lettuce is mature in 48-58 days,Romaine lettuce in 50-70 days, andcrisphead lettuce in 60-120 days. Youcan cut and sell all of the lettucetypes (except crisphead) before theyare mature. You can also pick and sellsome leaves from each plant at least3 weeks before they are mature.Many types of lettuce will keepgrowing leaves. Store lettuce at 33-35°F and 90-95% relative humidity.This way it can keep good quality forup to 2-3 weeks.

Spinach matures in 35-50 days andyou can start to harvest it earlier,when 5-7 leaves grow on the plant.Keep harvesting until the new leavesare too small or a seed stalk forms.Spinach keeps well for up to 2 weeksif stored at 32°F and a relativehumidity of 85-95%.

Swiss chard is mature in 50-60 daysbut can also be harvested early, about3 weeks before. Store chard for up to2 weeks at 32°F and a relativehumidity of 85-95%.

Asian greens are mature in 35-45days and can also be harvested early.You can start picking leaves after 4-5weeks. Asian greens will keep wellfor up to 2 weeks if stored at 32°F anda relative humidity of 90-95%.

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Preventing Stress

on Your Body

Try to prevent stress on your bodywhen you grow leafy greens.

✤ Try to prevent stooping or bending.

✤ Change your position often.

✤ Sit on a stool or a pail. You can usea stool that you wear as a belt, ora stool on wheels that rolls alongthe row like a cart.

✤ Use garden carts and wagons asoften as you can so you do not liftand carry so much.

✤ If you use a standard plasticcontainer that stacks and is easyto load, unload, and clean, you willsave time.

In the place where you pack yourcrops, try to have a smooth level floorso it is easier to work with carts andwagons. ✤ Set up your wash and pack area

so you walk, carry, stoop, andbend as little as possible.

✤ Set up work areas the same heightas a table.

✤ Short people might want to standon a stool to reach the tables morecomfortably.

✤ To move boxes of produce, thereare systems you can use withsmall pallets and hand pallettrucks.

✤ You can also buy roller table tomove heavy boxes of produce.

There are examples of tools thatmake work easier from the Universityof Wisconsin-Madison Department ofBiological Systems Engineering. Goto the department websitehttp://bse.wisc.edu/ and look under‘Department Links’ for the HealthyFarmers, Healthy Profits Project. Clickon Tip Sheets and go to the categoryfor vegetable growers. One exampleis a cart you can make to help harvestgreens.

Preventing S

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Weed Management

You must control weeds to grow agood crop of salad greens. Weedstake water, nutrients, space, and lightaway from your crop. Also, weeds leftin the field might be picked by mistakewith the salad greens. Before youplant, remove perennial weeds. Dothis by hand, by smothering with acover crop (such as buckwheat), byheating the soil with black plastic, orby using herbicide sprays. ✤ Cultivate or hoe regularly to

remove annual weeds. If youcultivate early in the season youprevent most weed problems.

✤ Cultivate shallow, not deep. Do notharm the small roots of the saladgreens.

✤ You will probably need to weed byhand also.

✤ If you use weed killers (herbicides),check the rules on the label.

✤ Certified organic growers can onlyuse approved organic weed killers.

If you use chemical weed killers, besure you check the label andunderstand that the one you chooseis legal for crops you sell. Chemicalslegal for a home garden might not belegal to use if you sell the crops.

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Pest and

Disease Management

The common insects that attack leafygreens are aphids, thrips, cutworm,leaf miner, and flea beetles.

Aphids and thrips are both tinyinsects you will see more easily with amagnifying glass. Look on the underside of leaves. Aphids have a softpear shaped body which can bewhite, yellow, black, brown, red, orgreen. They suck plant juices andtheir waste is a clear sticky sap.Thrips have a long, shiny body that isblack or yellow. They suck plant juicesand also cut into leaves, causing tinysilvery white spots. Both aphids andthrips can carry viruses into saladgreens. Viruses can cause disease.Keep your fields and the edges of

neighboring areas as weed free asyou can to prevent aphids and thrips.You can add helpful insects(beneficial insects) such as lady bugsto eat aphids and thrips. If the insectscaused a lot of damage, use a soapspray meant to kill insects.

Cutworms can also chew on youngleaves and stems. They are a long (1½” -2”) white larvae of a moth andthey curl into a “C” shape. Crush themto kill them.

Leafminers are small larvae from afly. The larvae eat and make tunnelsin between the top and bottom partsof a leaf. They live in soil over winter.Use row covers to protect plants.Remove leaves that have leaf miners.Also remove weeds that attract leafminers, such as lambsquarter andnightshade.

Pest and D

isease Managem

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Flea beetles are small (1/8” long)shiny black beetles that jump. Inspring and summer they eat smallholes in leaves and stems. Asiangreens attract flea beetles. Fleabeetles attack young plants moreeasily than older plants, and theyattack plants that do not have enoughwater or nutrients. Remove weeds toprevent flea beetles. Use row coversto protect plants.

Tipburn on lettuce looks like brownand rotted areas on the edges ofinside leaves. Tipburn happens whenthe lettuce plant loses more waterfrom leaves than it can take up fromthe roots. This is more commonduring hot weather when plants donot get water often enough and donot take up enough calcium. It is more

common on soils that have a lot ofnitrogen.

Fungal diseases also affect leafygreens and are worse when it is wet.Choose disease resistant varieties,plant in well drained soil or on raisedbeds, and space plants so air flowsbetween them. Water plants early inthe day so they can dry. Rotate cropsin a field to keep the spores frombuilding up in the soil. Sprays ofcompost tea may work to prevent andcontrol fungal infections.

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This publication was developed by the University of Wisconsin-ExtensionEnvironmental Resources Center in collaboration with the WisconsinDepartment of Agriculture, Trade & Consumer Protection and supported by agrant from the USDA Risk Management Agency.

Text by Astrid Newenhouse, Associate Scientist, University of Wisconsin-Extension Environmental Resources Center. Special thanks to Karen Delahaut.

Layout and design by Laurie Lawrence, Agency Art Director, WisconsinDepartment of Agriculture, Trade & Consumer Protection.

The publication can also be viewed and printed from pdf format on the web athttp://learningstore.uwex.edu/

Copyright 2010 by the Board of Regents of the University of Wisconsin System.University of Wisconsin-Extension is an EEO/Affirmative Action employer andprovides equal opportunities in employment and programming, including Title IX and ADA requirements. ISBN: 978-0-9821972-2-6

UWEX Publication A3904_01 (08/10)

WI DATCP pub#: mk_fc_79.qxp