September is a month of transition, both in life and in the garden. It’s back to school for the kids, and the end of vacation for many of us. Cities are back to their frantic pace.
Nature, too, is in transition, responding to the climate, which can’t decide whether it’s summer or autumn. We can have heatwaves as well as cool nights close to freezing. Some plants respond by changing color, while others, which prefer cooler weather, are at their peak.
In the garden, we’re taking advantage of the still-warm soil to sow, plant and transplant, while beginning preparations for winter. Harvests are plentiful, but are coming to an end, and some will have reserves for the cold season. Gardeners anticipate the coming year by sowing green manures, dividing perennials and planting bulbs that will bloom in spring.
In September, enjoy the end of summer, while preparing for winter and spring!
Vegetable Garden
- Harvesting kiwis: Keep an eye on the fruit on hardy kiwis and harvest when the fruit begins to soften;
- Corn harvest: Pick corn as soon as the silks start to turn brown;
- Late harvest for hardy vegetables: There’s no rush to harvest cabbages, Brussels sprouts, leeks and Jerusalem artichokes, as frost improves their taste;
- Ripening tomatoes indoors: Bring tomatoes indoors to finish ripening when night-time temperatures drop below 10°C. Do not place immature tomatoes in the refrigerator, as the cold will stop their ripening;
- Prevent tomato splitting: Keep the soil evenly moist to prevent it from drying out. This prevents tomato fruit splitting, often caused by humidity fluctuations;
- Frost protection: Be prepared to cover fragile vegetable crops if an early frost is forecast;
- Decomposing legume plants: After harvesting, leave pea and bean plants to decompose on site. They naturally enrich the soil with nitrogen for future crops;
- Cutting back old raspberry canes: After harvesting, cut back canes with brown bark to leave space for young, vigorous canes, ensuring abundant fruit production the following season;
- Sowing cover crops: Sow green manures such as fall rye or vetch to protect and enrich the soil over winter;
- Planting garlic: September is a good time to plant garlic so that it can begin to root before winter;
- Sowing autumn vegetables: In early September, you can still sow fast-growing vegetables such as spinach, arugula or radishes for an autumn harvest.
Ornamentals
- Dividing and transplanting perennials: Divide and move spring- and summer-flowering perennials at this time of year. Wait until spring for those in flower;
- Bringing annuals indoors: You can preserve certain so-called annual plants by bringing them indoors in autumn, either as seedlings or by taking cuttings, to protect them from the winter cold;
- Buying autumn bulbs: For the best possible choice, buy your autumn planting bulbs (tulips, narcissi, crocus, etc.) as soon as they arrive in the store;
- Bulb protection: To protect freshly planted tulip bulbs from squirrels, apply chicken manure or cover the ground with a piece of chicken wire after planting;
- Fall planting: September is a good time to plant new perennials, shrubs or trees, as the soil is still warm, which encourages rooting before winter;
- Watering after planting: Continue watering perennials, trees and shrubs planted this year until the first frost to ensure they survive the winter;
- Late-summer fungal diseases: It’s common to see a little white (fungal disease) on ornamental plants. Slow its progress by spraying with a solution of baking soda and insecticidal soap.
Lawns
- Installing or overseeding a lawn: The best time to reseed or install a lawn is in late August and September, although it can also be done in spring. Lawns prefer cool autumn temperatures and increased rainfall. On the other hand, if you sow too late, young seedlings, which are not yet hardened, may suffer from the first frosts;
- Grub nematodes: To treat grub infestations (larvae of common and European chafer beetles, as well as Japanese and rose beetles) in turf, use nematodes, small parasitic worms. Nematodes penetrate young grubs and inject them with bacteria toxic to them. Apply them when the grubs have just hatched and the soil is relatively warm, between 21 and 30°C (70 to 86?), generally between mid-August and mid-September;
Houseplants
- Bringing in houseplants: In early September, bring in houseplants that have been outside this summer. Prune or repot them if necessary;
- Preventive insect treatment: Before bringing in your houseplants, inspect them for insects and treat them if necessary to avoid introducing pests indoors.