You'll need a few pieces of information first.
* How long will your new crop take to mature? Information on crop maturity is listed on the back of seed packets. If you're buying transplants from the garden center, you should find this information on the plant tag for each plant. Because plants grow more slowly in the cooler, shorter days of late summer and fall, add a 7-10 day ″fall factor″ to the number of days to maturity listed on the seed packet or tag to take this seasonal difference into account.
* When is your first frost date? To find out your average first frost date, check with your local Cooperative Extension office, or look online at
* Can your new crop stand up to some cold weather? Some vegetables like cabbage, spinach, and radishes will happily keep on growing when weather gets into the high twenties F; even lower for super-hardy kale and collards. An early frost won't make a dent in these harvests.
Leeks, early carrots, beets, bush beans, early cabbage, broccoli, and collards take about 60 days to mature, so if your first frost date falls in mid-October, you still have plenty of time to plant and harvest these vegetables. There are lots of cultivars to choose from, but here are a few of my favorites. 'Lincoln' leeks can be harvested early, as finger-sized specimens, or allowed to mature at approximately 50 days. 'Thumbelina' carrots are ready to harvest at 50+ days and can be harvested early as babies. 'Bull's Blood' beets are ready to harvest in 35 – 60 days and their gorgeous, purple tops (can you call them greens?) are both edible and ornamental.
Leafy crops like chard, kale, arugula, and mustard greens can be planted in succession every few weeks, then harvested when their foliage is young and tender. No need to wait for them to mature, although you certainly may if you have a longer growing season.
Bok choy (aka pak choi) is an excellent short season crop and one of my favorite vegetables, period. It's delicious in stir fries or grilled whole on the barbeque. Some varieties ('Toy Choy'', 'Green Baby', 'Golden Yellow', and 'Tokyo Bekana') are ready to harvest in only 30 days.
Plant a second round of radishes, many of which mature in less than four weeks. 'Early Scarlet Globe', 'Cheriette', 'Cherry Belle', and 'Plum Purple' will all be ready to harvest in less than 30 days.
Cool season herbs like dill, chives, cilantro, fennel, and chervil grow better when planted later in the gardening season. They prefer the cooler temperatures of autumn to the summer heat and when grown for fall harvest, will not bolt, or go to seed, as quickly as earlier plantings. Depending on where you live, it might not be too late to plant a warm weather herb like basil. It's often ready to harvest in less than a month, and you can never have too much pesto.
Many gardeners maintain that crops planted later in the season grow better because there's less competition from weeds and the soil temperatures are higher, which results in faster growth. I think another reason for late season success is because we gardeners have relaxed after the initial frenzy of getting it all done in spring. We have more time to devote to individual crops and their specific needs.
So, if you think it's too late to plant an edible harvest, think again! There are plenty of vegetables and seeds out there waiting to fill a spot in your garden. And by August, they may even be on sale!
Ellen Zachos is the owner of Acme Plant Stuff (www.acmeplant.com), a garden design, installation, and maintenance company in NYC specializing in rooftop gardens and indoor plants. She is the author of numerous magazine articles and six books and also blogs at www.downanddirtygardening.com. Ellen is a Harvard graduate and an instructor at the New York Botanical Garden. She lectures at garden shows and events across the country.