It may seem hard to believe but it's already time to prepare for fall planting. In order for cool-season crops to reach maturity before the first frost in mid-November, we need to set out transplants or sow seed starting in mid-September.
September temperatures often remain too hot for many cool-season vegetables to do well. Radishes and carrots turn bitter and woody in the heat; spinach, lettuces and chard bolt (set seed prematurely); and peas drop flowers. A late hot spell can kill young transplants.
Here's a fall planting to-do list:
Check seed packet labels for "days to maturity" and count backward from Nov. 15, the average first frost date in our climate zone, to determine planting time. For better success in fall planting, choose seeds for varieties that have fewer days to maturity and which are described as "slow to bolt" and "heat tolerant."
Transplants started indoors from seed now will be ready for transplant in six to eight weeks and sturdy transplants should be able to withstand a few hot days in autumn better than tiny seedlings growing from seed sown directly into the soil.
Begin soil preparation in vegetable beds soon. Pull out determinate or bush tomatoes which have reached the end of their production; indeterminate or vine tomatoes, peppers and eggplants will continue producing through October.
Root vegetables such as radishes, carrots, beets and turnips need light, fluffy soil to reach full, good size. Spread a 2- to 3-inch layer of compost or humus over planting beds for root vegetables and till it in now to allow several weeks for the soil to settle.
If the soil is heavy clay, add gypsum or gypsite, which prevent clay molecules from binding together.
Our soil and water are highly alkaline; most leafy green vegetables are healthier with better flavor when grown in a lower pH, acid-type soil.
Add sulfur granules or crushed limestone when tilling beds for leafy greens to lower the soil pH. Peas and beans fix nitrogen into the soil and excess nitrogen will cause peas to produce more green growth than flowers when grown in the same spot for successive seasons.
Rotate all crops annually to prevent nitrogen buildup as well as the build up of soil-born diseases and pathogens.
If adding manure to the soil, make sure the product is sterilized — indicating that the manure has been heated to temperatures which kill disease pathogens and weed seeds. Allow at least two weeks for excess nitrogen from urea to dissipate before planting since high nitrogen levels in manure can burn roots.
Control for weeds before tilling and planting. Hand-pulling and cultivation with a wiggle hoe when weeds are small, before they set seed heads, are the best means of control.
If summer weeds in vegetables beds are mature with full seed heads, apply a non-selective herbicide to avoid spreading the seeds when pulled or cultivated. Read herbicide labels to verify that the product is safe for use near edible crops.