By Skip Richter
Fall is the best season of the year in the vegetable garden. Our warm-season vegetables are ripening in the milder days of fall, often accompanied by ample rainfall resulting in outstanding quality. The prime planting season for cool-season vegetables has arrived, so there is no lack of things to do in the garden. With the arrival of more tolerable temperatures, gardeners are emerging from their summer air-conditioned hideouts to spend more time in the garden.
Warm-season crops are well on their way to harvest, and our attention now turns to the cool-season crops that will be taking center stage. Here are some tips for getting the most out of your cool-season vegetable garden during these wonderful fall months.
Never miss an opportunity to improve your soil. The weather is still warm outside and organic matter, if kept moist, will decompose rapidly in these conditions. With every transition from one crop to another, mix an inch or two of compost into the soil and spade or rototill it in.
Raised beds can be helpful in areas of the state with lots of cool-season rainfall. They not only drain better but warm up a little earlier in the spring. By building planting areas up into raised beds now, you’ll be ready to plant in the coming months when the soil may be too wet to work. The benefits will carry on into the early spring planting season when your soil will already be prepared and ready to plant, no matter the weather.
Walkways are great for turning organic matter back into soil. Place leaves, grass clippings, spent hay or chopped-up spent garden plants in the walkways to create an all-weather pathway that slowly decomposes over time. I pile these organic materials up and walk on them, adding more over time as they sink down. Then once or twice a year, I “harvest” the walkways by pulling the undecomposed surface materials back and mining the composted materials underneath for use in my garden beds. You can make a lot of compost this way with very little effort!
Areas of the garden that won’t be cropped over the winter or areas for future garden expansion can be seeded with a cover crop in the fall. These cover crops, also known as “green manure” crops, grow through the winter as they protect the soil from erosion and create organic matter that can be mowed down and turned under a few weeks prior to spring or early summer planting. Some examples of cool-season cover crops include vetch, crimson clover, cereal rye, mustard and even bluebonnets! Hey why not have a little Texas beauty in that spot destined for a garden crop next May?
If you haven’t had a soil test in years or are planning a garden in a new spot, now is a good time to take a soil sample to evaluate the soil’s nutrient status. The results will guide you as to any fertilizer additions needed to prepare for productive future seasons.
Cheating Jack Frost
It is still hot outside, but winter is coming! Our warm-season crops are growing rapidly but will be slowing down as the days grow shorter and the temperatures get cooler. I find that my pepper plants are at their productive best in the fall season, so extending their productive life is worth the effort. Likewise green beans are their tastiest in the cool days of fall. I’ll have to wait until next May for another harvest of beans, so I want to do all I can to keep them going for now.
As the nights get cooler, it may help extend the season a bit to place rowcover fabric over the plants from late day until morning to hold in some of the soil’s heat and especially to fend off a light frost. Another technique is to place sections of 1/2-inch PVC pipe in arches down the row to support a clear plastic cover. This creates a mini-greenhouse or growing tunnel that will really warm up on sunny days. Use some soil around the edge to hold the plastic to the soil but leave the ends open during the day to allow excess heat to escape. Then close them down and place a weight on the plastic to hold in the warm air overnight.
When a freeze is forecast, plan on harvesting what you can from the warm-season crops before the plants are killed. Remember that tomatoes will continue to ripen indoors if they have reached a mature state. Leave them indoors at room temperature for ripening off the vine. Most other vegetables, including peppers, squash, green beans and cucumbers, won’t keep ripening after being picked, but they can still be eaten even when harvested early.
Success with Seeds
The temperatures are too warm in early fall for many of our cool-season, direct-seeded crops, including lettuce and spinach, to germinate well. We could always wait for cooler weather to arrive, but in order to get more from the fall garden there are two strategies for earlier planting.
I prefer to start these as transplants located in the outer shade of a large tree. This provides a break from the hot sun but still plenty of light to get them going. Once the seeds are up and have developed true leaves, they can be moved to part sun, then full sun, prior to being set out in the garden. This technique also helps when a warm-season crop is not quite done yet and garden space is limited.
The other strategy for earlier seeding is to plant directly into the garden but to shade the seed row with a section of shade fabric or rowcover fabric suspended over the row. Once again, PVC hoops work well, but anything that creates a shade canopy above the soil will help keep the soil much cooler and facilitate germination. I’ve also used sections of coat hanger wire and small T-shaped supports made from wood to suspend the shade cover.
Note the proper planting depth for seeds, as some need light to germinate and any small seed can easily be buried too deep. I have a set of soil screens that I use to screen compost and/or a soil and compost mix for lightly covering seeds. Another option is to use a section of 1/4-inch hardware cloth stapled to a wood frame for a fairly effective screen.
Water the soil prior to planting and press the seeds into contact with the soil after planting to aid in uniform germination and proper water absorption by the seed. Use a mister nozzle to wet the seed row after planting and avoid blasting them out of their location with coarse drops of water spray. Continue to maintain even moisture with regular wetting over the coming days. This will ensure prompt germination while keeping the seedbed a little cooler.
Tips for Transplanting
To some gardeners, using transplants is cheating. But when you are given a fall season where there isn’t much time between blistering hot and the first freeze, transplants are just plain smart gardening. Some crops don’t yield good results if transplanted. Root crops, for example, will end up forming deformed roots due to the restricted cells of the transplant container or to damage caused in the transplanting process. Cool-season peas are not fond of being transplanted and are just too easily direct-seeded anyway.
Transplanting is the best way to get a head start with cole crops, which include broccoli, cauliflower, kale, Brussels sprouts, cabbage, kohlrabi and collards, and work fine for the multitude of cool-season leafy greens, which include leaf lettuce, spinach, sorrel, arugula, cress, mache lettuce, parsley and Chinese celery.
The key to success with transplants is to start with a strong, rapidly growing transplant and to help it transition to its new home quickly. Stressed transplants, shock in the transplanting process and stressful growing conditions are recipes for disappointing results. Broccoli and cauliflower, under such conditions, become stunted and produce small heads.
Don’t be afraid to pop a potential transplant out of its container and look at the roots. They should be white and healthy, not gray or brown or wadded up circling the container, a sign of spending too much time in the container. Likewise the tops should be vigorous and a healthy green color. Purplish tints and smaller-than-normal leaves indicate nutrient deficiencies and stressful growing conditions.
Prepare the soil well by working compost into the planting beds. It is usually helpful to mix some fertilizer into the soil as you work it. I have found that lawn fertilizer works fine because it provides extra nitrogen for improved growth and vigor.
Set the transplants at the depth they were growing in their containers. Water the transplants in right away with a soluble fertilizer solution or a mixture of seaweed and fish emulsion, making sure to soak the root ball in the process. Continue to water them with the dilute nutrient solution for a week or two. We don’t want the plants to ever lack for water or nutrients while they are working to establish an extensive root system into the surrounding soil.
Hit the Accelerator
Once your cool-season plants are established, continue to maintain top vigor and health by never letting them lack for water or nutrients. While soggy soil conditions are detrimental to plants, it is important to water as needed to maintain moderately moist soil.
When plants are established, back off on the soluble feeding and work some fertilizer into the surface inch of soil around the plants for longer-term feeding. The best yields result from plants that are kept growing vigorously and healthy. Keep in mind that when cold temperatures arrive and the soil cools off, microbial activity slows and the release of nutrients is decreased.
Oh, No, You Don’t!
Tender seedlings are too tempting for hungry caterpillars or birds to resist. Transplants, like seedlings, are awfully tempting to marauding pests. Turn over a few leaves when you are out in the garden looking for any impending aphid or caterpillar infestations. Regular inspections will help avoid a disappointing and decimating invasion by unwelcomed fans of your tender salad cuisine.
While there are a number of different natural and synthetic insecticides that will kill various insect pests, I prefer to use a lightweight row cover to screen out the pests. Make sure the edges are held down with soil or weights to prevent anything from getting inside the protective covering.
Cool-season weeds are sprouting now. They won’t do much growing until late winter, but it makes sense to avoid weeding woes by preventing them from getting a start in your garden beds. Organic mulches of leaves, spent hay and newspaper over the soil surface will prevent weed seeds from establishing. Even if weeds have already sprouted, you can destroy them simply by blocking out their light with a covering of mulch.
Take advantage of the best season of the year for vegetable gardening. These tips can help you get the most from your cool-season garden and get a head start on next spring’s gardening too.