Take a walk outside now and the last thing on your mind might be fall gardening. Veteran gardeners know that despite the temperature, now is time to begin preparations for our fall gardens. Don’t wait until the weather cools off to begin or else it will be too late for some crops and tasks. Here are a few timely activities to create a bountiful fall garden, starting now.
CLEAN THE SUMMER GARDEN
Most gardens are looking spent by now, as weeds, pests, diseases and the assault of heat and drought have taken their toll. Begin your fall preparation by performing a general cleanup of the area.
Remove spent plants and discard them, along with their mites, insects and diseased foliage. Shredding and composting the plants are fine if you compost at high-enough temperatures, but it is often better at this stage to discard infested/infected plants.
Remove all weeds and discard them in the trash. Perennial weeds (such as nutsedge, Bermuda grass and Johnson grass) need to either be dug up (making sure to get all the underground rhizomes and/or tubers) or sprayed with a product that will translocate down into the underground parts to kill the plants.
PREPARE SOIL FOR FALL
Have your soil tested now to allow time to make the needed amendments before fall planting. Fertilizing year after year without a soil test can result in deficiencies, toxicities or significant imbalances.
Complete other soil preparations now so that when planting-time arrives, you are ready to go, even if the weather is rainy and the soil is too wet to work. Mix in any nutrients prescribed by your soil-test results. Spread an inch of compost over the soil (two inches if you haven’t added compost in the past year) and mix it into the soil.
Rain may be a distant memory now, but the fall season usually brings periods when too much of a good thing can waterlog root systems. Raised beds are recommended for areas that don’t drain well, especially in the eastern parts of the state.
ENLIST THE SUN
Solarizing is the practice of trapping solar radiation beneath clear plastic to superheat the top four-to-six inches of soil. This is where weed seeds and certain insect pupae (such as squash-vine borers) lie in wait. In a very sunny spot, the soil temperature can reach well over 140 degrees several inches deep when it is trapped by a clear-plastic cover.
It takes four-to-six weeks of hot, sunny weather to get the most benefit from solarizing soil. The process in a nutshell is:
• Remove all surface plants, weeds and mulch. Do any needed rototilling and bed formation prior to solar-izing to avoid bringing weed seeds to the surface later.
• Water the entire area well to thoroughly wet the soil.
• Cover the soil with clear-plastic sheeting and secure the edges of the plastic with soil to trap heated air.
• Wait four-to-six weeks before removing the plastic.
The following two free web publications are excellent sources of more in-depth information on solarizing in the home garden:
https://aggie-horticulture.tamu.edu/wp-content/uploads/sites/10/2013/09/soil_solarization.pdf
https://ipm.ucanr.edu/legacy_assets/pdf/pestnotes/pnsoilsolarization.pdf
MULCH, MUY, MUCHO, MUCH
Mulch is amazing stuff. Placed on the soil surface, organic mulches help prevent erosion and surface crusting, slow surface evaporation, moderate soil-temperature extremes and (in perennial garden beds) will decompose over time to build the soil organic-matter content. What other gardening product can do so much?
In one sunny location in mid-summer, the soil temperature registered 118 degrees one inch deep, while under mulch it was 88 degrees. That is a 30-degree difference! Even three inches deep, the soil reached 102 compared to 87 degrees under mulch — a 15-degree difference. These unmulched extremes significantly affect root growth and function. Case closed. Maintain mulch, three-to-four inches deep, over the soil in your summer garden.
When it is time to plant for fall, simply pull back the mulch just enough to plant into the cooler soil temperature, with no need for preplant weeding.
IRRIGATION CHECKUP
If you have not installed drip or other low-volume applicators, consider doing so now to make watering simple and easy. Were it not for drip irrigation and a hose-end timer, my plants would frequently report me to the SPCP (Society for the Prevention of Cruelty to Plants) due to watering neglect in blazing-hot summer weather.
If you have a low-volume irrigation system, now is a good time to give it a checkup. Pull the lines up to the surface, if they are buried in mulch. Turn the system on and check to make sure all emitters are working well. Replace or add emitters as needed to make sure all wetting zones overlap between emitters.
If you are using shrubblers or other squirting emitters on a stick, make any needed adjustments to the wetting-zone diameter to ensure thorough coverage. After running your irrigation system, dig down into the soil and make sure it is wet to at least six-to-eight inches deep.
PLANTING IN SUMMER HEAT
We need to plant tomatoes, eggplant and peppers in July; cucumbers and squash in early to mid-August; green beans and potatoes in mid- to late August to allow time for them to mature before the nighttime temperatures get progressively cooler, causing growth and development to slow.
Here are some tips to help get them going in hot conditions. Start most crops as transplants in an outdoor area with morning sun and bright mid- to late-day shade. When it is time to move them to the garden, temperatures will be moderating a bit, and it will be easier for the sturdy transplants to tolerate a full-sun location.
When starting crops from seed, begin by wetting the soil deeply a day or two prior to planting to provide the new roots a bank account of moisture. Sprouting seeds are vulnerable to dry conditions, and blazing heat significantly exacerbates the stress.
Provide a temporary shade structure for the seed row and over new transplants. There are many ways to devise such a shade structure, such as PVC hoops across the row to support shade cloth or a double or tri-ple layer of row cover to provide mid- to late-day shading for a few weeks.
Mulch’s soil-cooling effect is especially important for new plants trying to establish a root system. Water frequently to maintain consistent moisture in the surface few inches. Gradually reduce the frequency as the roots have had a chance to become more extensive and resilient.
PROVIDE PEST AND DISEASE PROTECTION
Pests are on the lookout for food, and the new “salad bar” you’ve provided is irresistible. I suggest that you cover plants after planting with a lightweight row cover or a garden-mesh fabric that reaches all the way to the soil to prevent entry. I’m a fan of the lightweight garden-mesh fabrics that have holes about the size of window screens, but which are very soft and flexible and as light as row cover. They allow light and water to pass through, and facilitate good air flow around the plants.
If you are not able to cover the plants, use Bt sprays for caterpillars, Spinosad sprays for beetles and caterpillars, and strong blasts of water directed upward to the undersides of the foliage to remove most of the spider mites and create an unhealthy environment for any mites that remain.
To minimize diseases, avoid wetting the foliage when you water. I don’t recommend constant spraying to prevent diseases, but be ready to take early action should fungal and bacterial foliage spots begin to appear.
Squash viruses are often prevalent in the late-summer to early-fall season. If these have plagued your squash in the past, mulch with sheets of aluminum foil held in place with bricks or bend pieces of clothes-hanger wire. One wide sheet of foil across the bed on each side of the newly emerged plants is sufficient to provide the sun reflection that deters the insects that infect plants with the virus.
Take advantage of some early-morning hours here and there to begin work on your best fall garden ever. There’s no need to get it all done at once, but a little brief work here and there now will set the stage for lots of enjoyment when the bounty and beauty arrive in the months to come.
By Robert ”Skip” Richter, M.S.
Host GardenLine
and Garden Success