Season Extension for Market Gardeners Oklahoma Women in Ag and Small Business Conference August 2015 Jim Shrefler Area Extension Horticulturist
What is Season Extension? Season extension refers to practices used to produce vegetable and fruit crops outside of the normal growing season Early planting in the spring Late planting & continued harvest in the fall Conditions that may be provided Warm the plant growth environment Protect from brief cold events Shorten the planting to harvest period
Season Extension for Oklahoma The previously mentioned practices Additional concerns Protection from adverse weather - wind, heavy rainfall, hail Difficult to predict climate What are usual weather conditions for Oklahoma? Pest and disease hazards these can prevent successful vegetable crop production even when the weather is ideal
Season Extension for Oklahoma The previously mentioned practice Additional concerns Protection from adverse weather - wind, heavy rainfall, hail Difficult to predict climate What are usual weather conditions for Oklahoma? Pest and disease hazards to crops these can prevent growing crops when weather is ideal
Seasons We Can Extend in Oklahoma Gardening Spring cool season vegetables- Plant earlier than normal Warm season crops Plant earlier Cold tolerant crops: corn, potato Cold sensitive crops: tomato, cucumber Warm season crops in mid summer Protect from the adverse conditions insects, intense sun and heat The fall garden Extend production and harvest later into the year
Early planting in the spring Situation during February thru April Wide temperature variation 20 80 o F; April freeze is possible Soil is cool; soil warming lags air temperature increase Days are short early on, but getting longer
Early planting in the spring Cold hardy crops Onions, lettuce, cabbage, carrots, English pea Can be planted in the open garden May benefit from floating row covers during freezes Black plastic mulch may speed plant growth Use transplants for onions, lettuce, & cole crops
Early planting in the spring Moderately cool tolerant crops Sweet corn, Irish potato Germination will depend on soil temperature Chill injury with low 30 s to 40 o F Use clear plastic for early soil warming Use row covers to protect from frosts & late freezes
Early planting in the spring Non cool tolerant crops Tomato, cucurbits, snap beans Start as transplants Temperatures in 30 s to 40 s o F will arrest growth Use black plastic for early soil warming Use row covers, hot caps, water walls to protect from frosts / late freezes
Another Reason for Early Planting Some warm season crops stop setting fruit with extreme heat Tomato, pepper, snap bean Objective: get crop producing before heat sets in Start as transplants Use row covers, hot caps, water walls to protect from frosts / late freezes If you area really serious, get a hoop house!
Another Reason for Early Planting Some warm season crops stop setting fruit with extreme heat Tomato, pepper, snap bean Objective: get crop producing before heat sets in Start as transplants Use row covers, hot caps, water walls to protect from frosts / late freezes If you area really serious, get a hoop house!
Fall and Winter Gardening Adverse conditions High soil temperatures Short days Common hazards Early frosts and freezes High pest populations Possible practices to use: Shade producing structures Irrigation Transplants Frost protection coverings
Fall and Winter Growing and Harvesting: Adapt to adverse conditions High soil temperatures Keep soil moist after seeding crops Shade soil surface until seedling emergence occurs Use transplants when feasible Short days Crop growth slows with shorter days and sunlight light intensity Smaller fruited crops may mature quicker (cherry tomato) Shade tolerant crop advantages (lettuce)
Fall and Winter Growing and Harvesting: Minimize possible hazards Early frosts and freezes in fall Pepper, cucurbits, beans could be covered with row cover material May be less practical for staked crops sprinkler irrigation an option for light frosts High residual pest populations in fall Check late season crops frequently Squash bugs a major cucurbit threat row covers may also help here
Row Covers
Row Covers Can Be Many Things Netting Clear or color plastic Glass Fabric Spunbound materials Others?
What Purposes Do Row Covers Serve? Modify temperature Keep things away from plants Keep things near plants Prevent things from falling on plants Reduce the impact of wind Modify color of plant environment A form of Insurance
What Purposes do Row Covers Serve? Modify temperature Extend the growing season Start growing earlier in the spring Continue growing later into the fall Protect from early and late frosts / freezes
What Purposes do Row Covers Serve? Keep things away from plants Insects Rodents (may not affect burrowers) Birds Larger animals Soil, ashes & other windborne particles Rainfall, snow & sleet Direct sunlight
What Purposes do Row Covers Serve? Keep things near plants Beneficial insects Pollinator insects
What Purposes do Row Covers Serve? Prevent things from falling on plants Airborne particles (ashes, residues from certain trees) Bird droppings Precipitation rain, sleet, snow, freezing rain
What Purposes do Row Covers Serve? Reduce the impact of wind Deflects wind away from crop plants
What Purposes ddo Row Covers Serve? A form of Insurance Protecting tomato plants from a frost Protecting from aphid infestation of squash can reduce chances of virus diseases Protecting from intense precipitation forms (hail, heavy rain) can prevent crop damage
What Purposes do Row Covers Serve? A form of Insurance Protecting tomato plants from a frost Protecting from aphid infestation of squash can reduce chances of virus diseases Protecting from intense precipitation forms (hail, heavy rain) can prevent crop damage
What Purposes do Row Covers Serve? A form of Insurance Protecting tomato plants from a frost Protecting from aphid infestation of squash can reduce chances of virus diseases Protecting from intense precipitation forms (hail, heavy rain) can prevent crop damage
What Purposes ddo Row Covers Serve? A form of Insurance Protecting tomato plants from a frost Protecting from aphid infestation of squash can reduce chances of virus diseases Protecting from intense precipitation forms (hail, heavy rain) can prevent crop damage
Putting Row Covers to Use in Your Gardening Think about what effects you need i.e. increased temperature?, less intense sun?, protection from insects? Think about what effects the different row cover materials will produce Think about the time period for producing an effect is needed
Modifying Temperature Plastics and other clear sheets Generally have a heating effect The Greenhouse Effect Spunbound materials and nettings Cool due to shading (not intended) Blocking wind may reduce cooling of breeze Shade cloths partial light blockage Reduce sunlight intensity Large temperature change under large areas
Practical Uses for Row Covers - - Enable Early Planting - - Clear plastic tunnels create a mini-greenhouse Often used with a black plastic mulch on the soil surface A raised bed will also help warm the soil earlier
Practical Uses for Row Covers - - Enable Early Planting - - Clear plastic tunnels create a mini-greenhouse Often used with a black plastic mulch on the soil surface A raised bed will also help warm the soil earlier
Practical Uses for Row Covers - - Protect From Insect Pests - - Cucumber beetles on seedlings Aphids that transmit viruses Squash bugs Moths of pest caterpillars
Using Row Covers to Protect from Insect Pests Materials Screen for larger pests Fine netting or spunbound fabric for small pests such as aphids Install cover before insects arrive Need to allow for pollinating insects to get to plants
Usefulness of Row Covers for Insect Exclusion in Squash? Is it practical? Is it cost effective? Are there drawbacks? What are the potential benefits? What are the specifics on when and how to use this technique?
Row Covers and Protection from Heat and Sun Plants need sunlight to grow In mid summer the sun intensity is more than what is needed by plants The combination of high air temperatures and heating caused by direct sun exposure can injure plants Fruits are especially susceptible
Materials used in Season Extension: Plastic Mulch Black Clear gets hot in sun! provides moderate soil heating greatest soil heating of the plastic mulches condensation helps with heat retention
Materials used in Season Extension: Plastic Mulch White may provide slight soil cooling sometimes combined with black or silver backing Colored red, blue, green, yellow specific uses for some Infrared-transmitting heating and weed control
Materials used in Season Extension: Non plastic Paper Mulch can provide benefits similar to black plastic biodegradeable special papers available shredded paper an option if available Organic mulches conserve moisture and suppress weeds insulate
Materials used in Season Extension: Row Covers Types Clear polyethylene Spunbound polyester or polypropylene Properties vary in thickness, weight & size When selecting, consider crop temperature sensitivity growth habit pollination
Materials used in Season Extension: Clear Row Covers A mini greenhouse Will get very hot in sunshine Some are vented Favor crop and weed growth Plan for controlling weeds Use with black plastic mulch
Materials used in Season Extension: Spunbound Covers Functions trap heat: 2-4 o F frost protection exclude insects block wind allow water passage Use 0.5 1.25 oz. per yard heavier gives too much shade thinner gives little protection
Economics?
Questions?