It's time to plant your garden.

Wait, what? You say you already planted?

Well, it's time to plant again.

August is a great time to start some vegetables to harvest in fall. While it's too late to plant tomatoes or other slow-maturing, warm-weather crops, the last days of summer are ideal for sowing seeds for leafy greens and root vegetables.

Think of it as a fresh start for procrastinators, or a do-over for those whose gardens got away from them. If you've pulled up your spent spring crops (radishes, peas and leaf lettuces), there's no need to let that garden real estate lay idle. You can replant in those empty rows or find space to tuck in a few plants for the second season.

There are plenty of pluses to growing fall produce — and a couple of caveats.

One plus? If you go to the garden center, you're likely to find that the seeds are on sale. You'll also find fresh seedlings of kale, Swiss chard and other greens ready to go in the garden. (Don't bother with raggedy leftovers from spring. Buy only starts designed for fall planting.)

Another plus? Seeds sown this time of year will germinate quickly in the warm weather, but will mature as the temps start to cool, without struggling through the high heat of summer.

Quick-growing veggies like leaf lettuces and mesclun can be snipped for salads as they grow. Radishes can be ready to nibble, sauté or pickle in less than a month. And there's no need to wait for all your beets and turnips to form. When you thin the rows, you can eat tops as baby greens.

Fall also allows for another go at fainthearted cilantro and leaf lettuce, which tend to bolt the minute the heat is on.

You're likely to see less damage from insects and other pests this late in the season, as well. And without as much heat and humidity to drive them, fewer fungal diseases will afflict your plants.

Picking the right varieties is important now that time is limited. Be sure to check the "days to maturity" on the seed packet, then count backwards from the first frost date, which is typically mid-October in the Twin Cities. (For more detailed information, check out the University of Minnesota's planting chart at www.extension.umn.edu/garden and search on "planting fall vegetables.")

Before you plant, clean out your spring crops by removing debris or diseased plant leftovers. Your first crop will likely have depleted some of the nutrients in the soil, so recharge it with a balanced fertilizer and some compost or aged manure.

Once the seeds or seedlings have been planted, keep them watered well while temperatures are still on the warm side.

While you'll have to pay attention to frost warnings, lots of cool season vegetables actually taste better after a touch of frost. It's said that exposure to light frost concentrates the sugars in kale, radishes, turnips and carrots, among others.

If an early freeze threatens, you can mulch with a thick layer of straw to help avert disaster. But I tend to go with the flow.

Fall gardening, like all gardening, is a bit of a gamble. Instead of fighting the cold, I cut my losses and harvest what I've got before a prolonged freeze sets in. (I call them "microgreens" or "petite vegetables," serve them up, and my guests are none the wiser.)

If you are planting tulip bulbs, consider growing some garlic, too. Garlic, like bulbs, are planted in the fall. Unlike flowering bulbs, the deliciously pungent bulbs of garlic will be ready for harvest in mid-July — just in time for tossing into your homemade marinara sauce.

Rhonda Hayes is a Minneapolis-based garden writer. She blogs at www.thegardenbuzz.com.