Complete gardening tasks in August to guarantee a fruitful flower garden and vegetable plot
August Gardening Tasks: A Guide for Flower and Vegetable Lovers
As summer reaches its peak, gardeners have a variety of tasks to keep their outdoor spaces thriving. Here's a rundown of what to focus on in August for both your flower and vegetable gardens.
Flower Garden
August is the perfect time to deadhead summer bloomers such as zinnia, vinca, cosmos, gaillardia, lavender, and other annuals and perennials. This practice encourages more blooms and keeps the garden tidy. However, avoid cutting plants back severely as they may not recover 1.
Planning for fall wildflower gardens, fertilizing container-grown flowers, saving seeds from summer flowers like sunflowers and marigolds, and ordering fall-planted bulbs (e.g., ranunculus, tulips, anemones) are also encouraged. Remember to cut sunflowers off just above soil level rather than pulling them up to avoid disturbing the soil structure 1.
Vegetable Garden
August is peak harvest time for many vegetables. Proper storage preparation is crucial for onions, potatoes, and carrots to ensure a supply into early winter. For onions, Allium cepa 'White Lisbon' does well in heavy clay soil and can be sown at this time [1].
Sowing seeds for cool-weather crops like cauliflower, broccoli, cabbage, kale, and Brussels sprouts should be done now to extend the growing season into fall. Salad crops should be sown every three or four weeks to ensure a supply into early winter [1].
Removing garden debris helps reduce pests, and top-dressing plants with compost and worm castings supports soil health. Container gardeners should move pots to afternoon shade, group containers closely for insulation, refresh soil mix, and avoid using small containers for a while 1.
Key Garden Maintenance
Key garden maintenance includes pruning rambling roses immediately after flowering if applicable, and planting fall-flowering bulbs before the end of summer to ensure rooting [3]. Tender perennials such as Helichrysum petiolare and Pelargonium tomentosum can be propagated by taking semiripe cuttings.
Getting tomatoes to ripen involves maximizing sunlight, reducing blight risk, and pinching out shoots and tops of the plants. Tomatoes other than 'Crimson Crush' may need to be sprayed with an organic copper spray or one containing baking soda to prevent blight [1].
Water features should be cleaned now to avoid disturbing wildlife during critical winter months. Don't forget to sow beetroot in late August for the roots to develop and leaves to be used in autumn and winter salads [1].
Herbs and Fennel
Perennial herbs should be given a good cut back now to recover before the cold months. Fennel can be sown under glass in August to reduce the risk of drying out and bolting [1].
Apples and Iris
Early apples can be harvested when the stem comes away from the branch. Summer is a good time to lift and divide bearded iris and order bareroot stock of new cultivars [1].
Planning Ahead
It's recommended to plan ahead for help in the garden, especially for watering and harvesting. Spring-flowering bulbs should be planned and ordered now for autumn planting.
For more detailed guidance on what to sow and plant in August, don't miss our guide. Aaron Bertelsen and Benjamin Pope provide advice for garden tasks in August.
[1]: Gardeners' World Magazine
[3]: BBC Gardeners' World [4]: The Guardian
- To encourage more blooms and keep the garden tidy, deadhead summer bloomers such as zinnia, vinca, cosmos, gaillardia, lavender, and other annuals and perennials in August.
- Container gardeners should move pots to afternoon shade, group containers closely for insulation, refresh soil mix, and avoid using small containers for a while in August.
- For onion, Allium cepa 'White Lisbon', sowing can be done in August in heavy clay soil to extend the growing season into fall.
