Gardening Beyond the Frost Britney Hunter Horticulture Extension Faculty Davis County 1
250,000 Tiny Greenhouses, Each Containing One Head of Lettuce 2
Overview Intro to high tunnel greenhouses Understanding weather Temperature management Growing calendar 3
High Tunnels 7 14 2 Walk in, drive in Don t overheat as quickly as low tunnels Space for mature plants 4
42 x 14 USU High Tunnel 72 plants per tunnel ~10lb per plant = 720 lbs! 5
Backyard Warm Season Tunnel Zucchini Tomatoes Winter Squash Peppers Beans 6
Don t try to create an endless summer; instead, work with the Farm manger, Barbara Fuller. La Nay Ferme in Provo seasons. 7
Understanding the Weather Wind and frost (the true garden killers) 8
Freeze Free Period (a.k.a Growing Season) Jan Feb Mar Apr May Jun July Aug Sept Oct Nov Dec Location Freeze Free Period (AVERAGE) Logan (Cache) May 14 Sept 26 (125 days) Brigham City (Box Elder) May 4 Oct 11 (159 days) Kaysville (Davis) May 1 Oct 13 (165 days) Salt Lake Airport April 26 Oct 18 (175 days) Provo (Utah) May 1 Oct 12 (165 days) Moab (Grand) April 17 Oct 17 (184 days) Utah Climate Center http://climate.usurf.usu.edu/reports/freezedates.php 9
Frost vs. Freeze Definition of frost/freeze warnings issued by National Weather Service. Warning Wind Speed Air temperature Frost Below 10 MPH Above 32 o F Frost/freeze Below 10 MPH Below 32 o F Freeze Above 10 MPH Below 32 o F 10
Night Time Radiation Freeze 32 F 11
GROWTH RESPONSE TO TEMPERATURE 12
Temperature Responses Cool Season Crops Crop Min Opt Max Onion 45 55-75 85 Cabbage 40 60-65 75 Salad 45 60-65 75 Potato 45 60-65 75 Perennial 45 60-65 80 Warm Season Crops Crop Min Opt Max Bean 50 60-70 80 Corn 55 65-75 90 Melon 55-60 70-80 90 Tomato 65 70-80 85 Sw Potato 65 70-85 95 13
How does it work? The original greenhouse effect 14
Managing temperatures How cold or heat can plants tolerate? High tunnel Low tunnel Floating row cover Ventilation and shade 15
Cultural and Environmental Microclimates Plastic mulch Raised beds 16
Type Protection *near freezing Covers Advantages Disadvantages Cost/10 tomato plants Row cover cloth (Reemay ) 2-4 F Can leave on Can blow around, not air tight Plastic 2-4 F Air tight Needs support Must ventilate Plastic + cloth 4-13 F Better protection custom size Needs support Must ventilate Wall o water 10-22 F Can leave on Size, not air tight $33 Plastic/glass cloche 2-5 F Air tight Size, must ventilate $80 $15 $18 $33 Paper cloche (HotKap) 2-4 F Inexpensive flimsy, limits light $10 *Environmental factors prevent 100% accuracy 17
Air Temperature with Soil Heating Cables 18
Cold Frames Temperature Protection depends on materials (2-10 F near freezing) Advantages Sturdy Compatible with automatic opener Greens year round Disadvantages Not big enough for mature plants Overheat quickly 19
Tunnels Temperature Lift 2-4 F near freezing Added protection by stopping wind (hard to measure) Advantages Tall enough to grow most plants Can be built for individual needs Disadvantages Must be ventilated Can get expensive 20
Tunnel Design: Low Tunnels Heat up quickly Not tall/wide enough for mature plants Insect net 21
Colorado State Extension http://www.ext.colostate.edu/mg/gardennotes/722.html 22
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The Yearly Growing Calendar - Mellow Management: Season Extension - Small scale growers - Backyard gardeners Seed indoors warm Crops Direct seed Thanksgiving cold crops Transplant Thanksgiving cold crops Cool Crops Warm Crops Cool Crops Jan Feb Mar Apr May Jun July Aug Sept Oct Nov Dec 24
Time Line Garden High Tunnel COOL SEASON Seed lettuce Jan 15 - Feb 15 Plant lettuce Feb 15 - Mar 15 WARM SEASON Seed tomatoes Mar. 1 Plant tomatoes April 15 COOL SEASON Seed spinach Aug 1 - Sept 1 Plant spinach Sept 1 - Oct 1 25
Idea for winter watering: Use a large water tank for watering in the cold season If by chance it does freeze solid, it will likely be during a time when you don t need water 26
First Harvest July 7, 2009 Outdoors: ~ August 10 27 27
Warm Season Tunnel Zucchini Winter Squash Tomatoes Peppers Beans 28
Late July in Warm Season Tunnel Lots of powdery mildew on the winter squash and zucchini Tomatoes and peppers are doing well beans have yet to blossom no fruits on the melon 29
Considerations for Success Drip irrigation Plant spacing Temperature requirements Fertilizer Pollination 30
Summary: Covers and structures increases temperatures during the day so plants start growing earlier, and will fruit sooner. Ventilation and cooling is critical Covers and structures protect plants a little at night, but plants can still freeze 31
Selecting a Design Type Ideal Situation Why to use Why not to use Cloth Cover Few plants Easy Benefit is limited Cold frame Fanatic about greens Easy Not big enough for tomatoes Low tunnel Don t mind ventilating Custom size If you forget, the party is over High tunnel Farming/ small business $ Premium Ventilation and maintenance 32
extension.usu.edu/publications Illustrated web version 33
Soil amendment and aeration Between crops Keys to Success Seeding tool makes it easy and fun Wire support increases efficacy and keeps the cloth clean 34
SNOW LOAD 5-6 35
Cost/Economics 14 x 42 $500 (materials) FarmTek 14 x 24 $800 to $1000 (materials) 36
USU Garden Tunnel $260.00 37
Other Resources 38
Questions? http://extension.usu.edu 39