July is a pivot point for Ontario gardeners, transitioning from spring planting to mid-summer succession and fall harvest planning. Despite the peak summer heat, this month offers a significant opportunity to maximize garden output. Strategically planting fast-maturing varieties now ensures a continuous supply of fresh produce through late summer and extends the harvest well into autumn.
Quick-Maturing Vegetables for Summer Harvest
Focusing on vegetables with a short days-to-maturity (DTM) allows for a quick second harvest before the weather cools. Bush beans are an excellent choice, thriving in warm July soil. Many varieties, like ‘Contender,’ are ready for harvest in 45 to 50 days from direct seeding, meaning fresh pods by late August. Direct-sowing is preferred since beans do not transplant well.
Quick root crops like radishes and short-season carrots are also ideal for a July planting. Radish varieties, such as ‘Cherry Belle,’ mature rapidly, often in under 30 days, providing a fast turnaround in garden space. Even carrots have fast-maturing varieties like ‘Little Finger,’ which can be ready in 55 days. Beets can also be direct-sown now, maturing in 50 to 70 days, and they often develop a sweeter flavor when matured in the cooling soil of late summer. Leafy greens, including spinach and arugula, can be planted now, but should be sown in a partially shaded spot to prevent the high heat from causing them to bolt quickly.
Preparing the Garden for Fall Crops
July is the final window for planting crops requiring a longer season to mature before the first frost, which typically occurs in Southern Ontario from late September to mid-October. This timing is important for the brassica family, which prefers cooler weather for maturation. Broccoli, cabbage, and cauliflower should be transplanted in late July, as starting them from seed now would not allow enough time for full head development.
These transplants should ideally have been started indoors four to six weeks prior to July, as the intense heat of mid-summer can be difficult for young seedlings. Cool-weather greens like kale and collards can be direct-seeded now; they are extremely frost-tolerant and their flavor actually improves after being touched by a light frost. July is also a good time to plant a second crop of potatoes that can be harvested later in the fall. Peas, a cool-weather crop that can tolerate light frost, can be planted now for a fall harvest, with many varieties maturing in 60 days, yielding a crop by early September.
Mid-Summer Herbs and Flowers
July is a great time to ensure a continuous supply of fresh herbs and vibrant color for the remainder of the season. Heat-tolerant herbs such as basil, mint, and oregano thrive in the intense summer sun. Basil can be continuously succession-planted from seed throughout July, offering fresh leaves until cold weather arrives. Providing afternoon shade can prevent stress during extreme heat.
Cilantro, which bolts quickly in summer heat, can still be planted if placed in a shadier spot and kept consistently moist. For ornamental interest, many annual flowers can be sown now to bloom until frost. Zinnias are a resilient choice, known for their bright colors and impressive heat tolerance, blooming continuously throughout the summer. Cosmos and calendula are also excellent options for reseeding in July, as they are fast-growing and attract pollinators until the end of the season.
Managing Heat Stress for New Plantings
Successfully establishing new plants in July heat requires specific techniques to mitigate environmental stress. The primary practice is deep and infrequent watering, rather than shallow daily sprinkles, which encourages the development of deep, resilient root systems. Watering should be done early morning or late evening to minimize evaporation and ensure moisture soaks into the root zone.
Applying a thick layer of organic mulch, such as straw or wood chips, is another highly effective strategy. Mulch acts as an insulating blanket, dramatically reducing soil temperature fluctuations and slowing moisture evaporation from the soil surface. Providing temporary shade is important for delicate transplants or leafy greens, especially during the hottest parts of the afternoon. A simple shade cloth with a 30 to 50% shade rating, supported over the plants, can lower the ambient temperature and prevent sunscald.