If tomato plants get too much nitrogen, they'll produce lots of lush green foliage and plenty of flowers, but the blossoms won't set fruit. So instead of blasting them with granulated fertilizer, give your plants a boost with a dose of fish fertilizer or a half-strength dilution of liquid fertilizer. You'll keep those ripe tomatoes coming through the rest of the summer.
Practice Good Garden Sanitation
When your veggie beds have finished producing, rake and clean them to remove spent foliage and other debris. Slugs, bugs, and disease pathogens prefer unkempt gardens to clean ones. By removing their favorite hiding places, you'll reduce the amount of insect damage and disease in your garden.
When you've finished harvesting vegetables and it's time to remove the plants, be sure to add them to the compost pile, along with your grass clippings. Keep the pile turned and aerated. If kept moist and well tended, it will produce more great compost for the garden this fall.
Prolong Blooming of Roses
Feed, water, and mulch roses now to keep them blooming well into the fall. This will also protect them from drying out if hot weather persists. Use a fertilizer high in phosphorus, such as 15-30-15, to promote blooms rather than foliage.
Prune Flowering Shrubs
After flowers are spent, prune back summer-blooming shrubs such as escallonia and viburnum. Pruning too late in the summer will remove future flower buds and encourage stem growth that won't have time to harden before the weather turns cold. As you're reducing the height of tall shrubs and removing errant branches, be sure to thin excessive growth in the center of the shrubs. This will allow sunlight to penetrate and encourage the formation of additional flowering branches.