Maximizing your vegetable gardening harvest means pushing the limits of the Ontario growing season. Given our somewhat unpredictable spring and autumn weather, techniques to extend the harvest period are essential. By preparing for the cooler months and protecting your crops, you can continue to enjoy fresh vegetables well past the first frost and dramatically increase your annual harvest.
Five Practical Strategies for Extending the Gardening Season
1. Start Seeds Indoors During the Summer for a Fall Harvest
Mature cool crops can easily withstand light frosts, but their seedlings grow very slowly in cold outdoor soil. You can circumvent the short growing season by starting new cool-weather seeds indoors for four to six weeks and then transplanting the semi-mature plants into your garden in September and early-October.
- Benefit: This process shortens the time plants need in the outdoor garden, allowing you to maximize space and continue harvesting into November and December.
- Best Crops: Lettuce, kale, chard, mache, spinach, and collards.
- Advanced Tip: Use this technique for succession planting the slower-growing cool crops by starting seeds (such as Brussels sprouts or broccoli) in mid-summer, ready to transplant outside once your earlier hot crops are finished.
- For more on this technique, visit our mini guides on Succession Planting and Starting Seeds Indoors.
2. Protect Crops with Row Cover and Cold Frames
Physical protection is key to safeguarding your plants from autumn frost. These transparent coverings also shield crops from extreme precipitation and pest infestation.
- Row Cover: Fabric placed atop hoops that offers protection while still allowing some sunlight and rain through. This is the most cost-effective and easiest solution to implement and store.
- Cold Frames: Rigid structures, often wood frames covered with plastic or glass, that offer superior protection from heavy snow or extreme wind.
- Crop Considerations: Since these structures block some sunlight, focus on plants that tolerate part-shade, such as lettuce, chard, baby kale, and mache. Note that roots and leaves may be smaller than normal due to the reduced light – but they’ll still be delicious.
- Pro Tip: Consider heavier frost blankets as an excellent compromise between row cover fabric and cold frames.
- Learn more about this equipment in our Row Cover guide.
3. Manage Your Soil and Protect Roots
Bare soil loses heat quickly and is vulnerable to water freezing on cold days. Do not leave the soil exposed during the cooler months.
- Mulch: Use wood chips, straw, or black landscape fabric beside and beneath your plants. This helps hold residual heat and reduces the risk of water freezing in the root zone.
- Cover Crops: Plant cover crops (like winter rye or annual clover) in the late summer or fall in any bare spots in the beds. They serve the same function as the mulch, while also improving soil quality when incorporated in the spring.
- Find more details on this in Putting Your Garden to Bed For the Winter.
4. Strategically Plan Your Fall Planting and Harvesting
Success in gardening depends on planting crops whose maturity aligns with the declining temperatures. Always check the long-term weather forecast to anticipate early frosts.
- Focus on Cool Crops: Focus exclusively on fast-growing, cool-season vegetables like lettuce, spinach, radish, and mache, as these will still germinate quickly during cooler nights.
- The Hard Frost Rule: Cool crops will produce until the first hard frost. If one is forecasted, harvest your vegetables aggressively beforehand, or ensure your cold frame or row cover protection is securely in place.
5. Save and Overwinter Tender Perennials
For established plants that are perennial in warmer climates but cannot survive an Ontario winter, you can bring them indoors to save them for next season.
- Examples: Peppers, rosemary, and hibiscus.
- Benefit: Overwintering established plants provides a much quicker harvest and higher yield the following spring compared to starting from seed, effectively lengthening your harvest window.
- For specific instructions on this technique, see Taking Tender Plants Inside For the Winter.
Ready to Grow More?
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