The Pee Gee hydrangea is one of several plants that will continue to bloom well into the fall. Donna Balzer / For CREB®Now

Aug. 30, 2017 | Donna Balzer

September in the garden

Gardening tips as autumn arrives

I walked the dog in a sweater this morning. Soon I will be wearing my down jacket. So, is this all we get? Is it the end of the garden season? No way!

Hold your horses and follow these dos and don'ts to get the most out of our shrinking garden season this month.

Do leave your potatoes, beets, parsnips and carrots in the ground as long as possible, even if the potato tops die and the plant looks dead. These root crops get sweeter as the soil gets cooler and they will easily last in the ground until Thanksgiving. For best flavour, pick as you eat. You are not running a market garden, so you don't need to harvest the whole row now.

Don't add anything blooming or with seed to your compost. This spring, I had lettuce and flowers sprout in my garden thicker than hair on a dog. And that was before I planted anything. The trouble is everything volunteered – it was growing from the compost I spread. The seedlings were so tightly packed, and the sprouts so skinny, I had to pull them all out and start again in June. If you don't remove mature flowers and seeds from the stems before you compost them, they will sprout like so many packets of seed dumped in one place next spring.

Do start picking tomatoes, even if they are green. Cool nights – when temperatures are lower than five degrees Celsius – cause black spots on tropicals like tomatoes. Melons, squash and marigolds also die early when evenings get cool. Pumpkins are the lone exception. They can be left in the ground through frost, but if foliage starts turning white with powdery mildew disease, remove leaves one by one. Pick tender fruit now and let it ripen indoors. Go to the liquor store and get the shallow boxes that originally held flats of beer and use these as trays to hold your tomatoes or squash in single layers under your bed. The fruit will slowly ripen for several weeks.

Don't pull out your flowers or mow down your garden – the season's not over just yet. Instead, leave blooming plants, such as fall-coloured asters, Rudbeckia, geraniums, Pee Gee hydrangeas and hardy petunias alone, as they will keep on blooming. A few plants, such as marigolds and zinnias, will die, but you can selectively pull those out as you walk past, leaving the hardier plants to flourish. There is nothing sadder than a landscaping crew completely flattening a garden just 90 days after it was planted. We still have at least two months of summer and fall interest in the garden left, so let it bloom!

Do seed lettuce, spinach, pak choi, radish and mustard greens in empty beds any time this month. The goal is to get the seed into the ground in fall so it will sprout earlier next spring. Let your lettuce go to seed and spread by itself, or collect the seeds and plant them in the beds where potatoes have been dug or peas have been removed.

Donna Balzer is an enthusiastic gardener and speaker. Sign up for her e-newsletter at www.donnabalzer.com for regular updates and garden info.