The arrival of high summer is one of the turning points of the garden season. While we have enjoyed long, luxurious daylight for nearly two months, that will soon change--and fast! A month from now, our days will be a full two hours shorter, and the first hint of fall coolness will likely visit during a starry night or two.
This process of shrinking daylight will continue until December. Its primary effect on the garden is slowed plant growth. While in spring the lengthening daylight encourages faster and faster growth of young seedlings, the same cool-season crops grown for fall harvest require about two extra weeks to reach harvest size due to the steadily reducing sunlight.
For this reason, it's important to start crops for fall harvest well before it actually feels like fall. They just won't grow fast enough otherwise.
Not sure what to plant for fall--or when? Here are a few specific examples.
- Cukes and Zukes and Green Beans. This is the last chance to sow some more green beans, cucumbers, and summer squash; seeds sown now will mature from mid-September into October. The quality of these crops in fall is much better from July sowings than from older plantings, so don't hesitate--sow today!
- Fall Peas. Growing peas in the fall is trickier than growing them in the spring--primarily because the young plants love cool temperatures. They need to be sown by the end of July for a decent harvest, which means they need irrigation and--if possible--shading to pull through the heat of high summer. Once cooler weather sets in, though, they thrive, and you can achieve a harvest that, though always less than the spring peas, is still a great bounty.
- Lettuce. Lettuce sown from now until early September will achieve full size before deep freeze conditions set in. The later you sow lettuce, the more you should focus on dense sowings of baby-leaf mixes rather than going for big heads. Fall sown lettuce (late September and early October) will overwinter with a little mulch for your earliest April and May eating (or earlier if grown under row cover).
- Turnips. Sow in early- to mid-August for harvest in late October. So sweet and delicious in fall, you'll want to grow them every year.
- Asian Greens. Sow bok choy, tatsoi, and other Asian Greens in the Mustard family from now until late August--or even later. Many of these crops hang on tenaciously through cold spells; fall crops will delight you with their sweet flavor and (relative) lack of damage from flea beetles.
- Kale and Collards. Start as soon as possible in order to get as large leaves as possible before the plants "shut down" as day length diminishes in November. These crops can be harvested until the new year, even when covered in snow. Well worth the effort--and so much sweeter and appealing in the fall than in the summer.
- Radishes. Sow in late August or early September, depending on variety; daikons can be sown earlier. Do a few sowings in succession for smallest, best-flavored roots into November. Roots get bigger in the fall and do not bolt, so be prepared to roast some if they swell before you get the chance to harvest them.