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Growing Greens in High

Tunnels

M. D. Orzolek

Department of Horticulture

The Pennsylvania State University

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Mixed green production

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Types ofLettuce

1-Romaine - green and red 2-Bibb - green

3-Oakleaf - green and red

4-Butterhead - green and red

5-Summer Crisp (Batavia) - green and red

6-Baby lettuce mixtures - mild mesclun mix,spicy greens mix, braising mix.

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Lettuce Maturity

Lettuce types range in maturity from 42to 58 days for full size heads. Babylettuce types are ready from seeding to

harvest in 28 to 30 days. Cooler airtemperatures, below 40F will slow

growth of lettuce plants and increasetime to maturity 7 to 10 days.

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Types of Leafy Greens

1-Asian greens - Hon Tsai Tai, Chinesekale

Komatsuna, Mibuna, Mizuna and

Tatsoi.

2-Arugula

3-Pac Choi

4-Corn Salad/Mache

5-Cress

-

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Leafy Green Maturity

Leafy green types range in maturity from 35to 55 days for full size heads. Baby greenstypes are ready from seeding to harvest in 21

days. Cress will mature in 10 to 12 days fromseeding. Cooler air temperatures, below32F will slow growth of leafy green plants

and increase time to maturity 10 to 15 days.

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Mizuna

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Tatsoi

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Arugula

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Environmental Requirementsfor Seeding Lettuce

Lettuce is a hardy, cool season cropthat can be grown in high tunnels 12months of the year. Optimum growth

occurs at temps between 60F to 65F.Seeds will germinate at soil

temperatures as low as 40F, but poorlyat soil temperatures above 75F.

Requires firm seedbed and continuous

soil moisture for germination.

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Direct seeded lettuce in HT

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Dense population of lettuceeliminates weed problems

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Lettuce emergence fromOctober seeding

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Fall Seeding of LettuceUnder Row Cover

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Production of Lettuce inSummer

Many varieties of lettuce grown underhigh summer temperatures (85F orhigher) for 5 to 7 consecutive days are

susceptible to bolting. Choose lettucevarieties when growing in the summer

that are resistant to bolting.

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Establishing Leafy Greens inHT

Seeding especially of baby lettucemixtures from mid-May through lateAugust. Vigorous seed germination and

emergence critical for maximum yieldsand quality.

Transplant production for late winterand late fall production.

Use of 128 or 200 cell trays will produce

ideal transplant in 14 to 20 days.

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Environmental Requirementsfor Lettuce Transplants

Seed in 128 or 200 cell trays with shallowplacement in soil (0.25 deep) and cover withfine vermiculite. If temperature in

greenhouse or high tunnel exceeds 75F,place shade cloth above trays to keep cool.

Harden transplants by reducing water or temp

2 to 3 days before planting in high tunnel.Hardened transplants can survive air tempsas low as 20F.

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Lettuce Transplants - 72 celltray

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Lettuce in High Tunnels

Plant spacing of seeded lettuce,especially salad mixes, approximately60 seeds/ft. in 4 to 6 wide band.

Minimum spacing between bands willdevelop continuous plant canopy and

help reduce weed seed germination.Spacing of transplants in raised beds

should be dense enough to reduce

weed growth in beds.

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Multiple planting of leafy

greens in permanent raisedbeds

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Use of shade cloth to enhancegermination of lettuce seeds

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Poor lettuce spacing can

produce sparse plant canopyand weeds

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Mature raddichio

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Romaine lettuce productionin foreground

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November lettuce productionwith row covers

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Spring Lettuce Production

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Biological Control of Aphids

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Rodent Control

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Cellar Market on Campus

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Interior of Cellar Market

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Are There Any Questions