Plant seeds of overwintering cover crops by September or early October before the weather turns too cold and wet for them to germinate and get established. Make sure when you plant that the seed has good contact with the soil. Larger seeds like peas, vetch and cereals should be raked in lightly.
All cover crops have limitations, as no plant can provide every desired benefit. Major limitations include the cost to establish cover crops, the time required to plant during the busy harvest season, and required additional management/planning.
Starting in mid to late September, it is beneficial to watch the forecast and take note of forecasted low overnight temperatures. Once temperatures dip to the mid-30s °F, it will be necessary to take action by bringing plants indoors, covering plants, or utilizing cold frames and hoop tunnels.
Cover crops should be planted soon, so they get as much sun as possible as we head into winter. For the beginner, a cover crop seed mix is easiest – it should contain both legumes and cereals (like oats, barley or rye).
Cover crops are broken into two camps: ones that are killed by winter temperatures and ones that spring back to life in spring. The former are good to plant in beds dedicated to early season crops, such as onions or greens, because these beds will be ready to work as soon as spring weather cooperates.
Most winter cover crops are planted by mid-October with the exception of annual ryegrass, which is probably the most cold tolerant. At this point you would likely be better off mulching the soil with compost, separated dairy solids, leaves, or even cardboard or newspaper to provide some soil cover.
Cover Crops Improve Water Quality
“So, if you do cover crops year-after-year, you see improvements in soil health, which ultimately lead to more resilient soils, better crop yields, and more conservation of resources,” said Kidwell-Slak.
Cereal grains, such as rye and wheat, and ryegrass are typically the least expensive cover crops. Single-species rye, wheat or oats can be an excellent option for many farms. Single-species cover crops are cheaper and typically easier to terminate.
Mustard and rapeseed are used as cover crops and have been shown to suppress some soil borne pests. When the mustard plant that is still green is incorporated into the soil and decomposition starts, glucosinolates are released. The breakdown products of these glucosinolates are thought to have biofumigant properties.
Each plant has a different threshold when it comes to dealing with the cold. Some plants can survive outside even when temperatures hit freezing. Others need to be brought indoors when temperatures reach the mid-40s. Be sure you know this before you plant.
Late February–early May for summer cabbages (protect early sowings with cloches or fleece) April–May for autumn and winter cabbages.
Nobody likes to thin seedlings. It's fussy work, and always hard to decide which ones to save and which to toss. Here's and easier way: When the first true leaves appear, snip off the extra seedlings at the soil line. You'll be left with only as many seedlings as you need.
If cover crops are so great, why do so few farmers use them? Well, there are a few negatives: Cost $30-50 per acre with no direct return. May take at least 3 years to see a benefit, an issue on rented ground.
In no-till farming, farmers do not till their fields before planting. Instead, they use specialized equipment to create a channel that is just spacious enough for seeds to be planted, minimizing soil disturbance.
Cover crops (grasses, legumes and forbs) recommended for seasonal cover and other conservation purposes include annual ryegrass, oilseed radish, winter cereal rye, and oats used for scavenging unused fertilizer and releasing nutrients back into the soil for the next crop to use.
Growth Rate: Buckwheat, Berseem Clover, Austrian Winter Pea, annual ryegrass, and oats are all fast-growing crops ideal for providing quick cover between crops or on sensitive sites.
Drawing data from farmer surveys, the report estimates that seed costs for cover crops can vary from $10 to $50 an acre. The seeding of the cover crop can cost $5 to $18 an acre, and termination expenses can amount to as much as $10 an acre. The total median cost is $37 an acre.
Cereal Rye – The King of Cover Crops. As farmers and ranchers alike navigate the world of regenerative agriculture and cover crops, the humble cereal rye plant (Secale cereale) has been making a name for itself as the undisputed King of Cover Crops!
Sunn Hemp is another popular warm-season cover crop to grow in the vegetable garden. This variety works well in sandy soils or nutrient-poor soil types and is another cover crop that adds improved organic matter and suppresses weed pressures.
Cons to Cover Crop Planting
Additionally, cover crops may reduce or increase the soil's moisture effects based on weather conditions or management practices. Furthermore, cover crops may be difficult to include with tillage. Occasionally, cover crops increase insect pests and disease.
Plant in mid to late fall, will survive the winter
Overwintering cover crops can be planted after late harvested crops like tomatoes and peppers. They are also well suited to fall manure applications because they can hold nutrients through winter and spring snow melt.
Grazing and harvesting
Grass cover crops are more profitable than legumes or cover crop mixtures because the seed costs are affordable and the biomass production is higher. Four studies quoted showed annual net return from grazed or harvested cover crops ranging from $17-$122 per acre.