Late Crops, Seed Collection and Other August Gardening Tips

August is peak time for backyard gardeners. There’s an abundance to harvest and plenty to do. “It’s a great month to be out in your garden, both enjoying the fruits of your labor and starting to prepare for the fall growing season and for next year,” says Jason Reeves, research horticulturist and garden curator at the University of Tennessee Gardens in Jackson.

Reeves’ August Gardening Tips include:

• Begin collecting seed of annuals and perennials for next year’s garden. Cut seed heads and place in brown paper bags to dry, labeling each bag with the name of the plant.
• Sow pansies, ornamental kale and cabbage, and Swiss chard seed in a good quality potting medium. After seedlings develop true leaves, transplant them into individual cell packs or pots. Feed with a water-soluble fertilizer. By late September or early October they should be ready to transplant into the garden.
• For late crops of beets, carrots, collards, kale, lettuce, spinach, turnips, mustard and radish, sow seeds before the middle of the month. Transplants of broccoli, cabbage, cauliflower, and onions can be planted mid to late August.
• Stop watering amaryllis bulbs late this month and place them in a dry location. After leaves turn yellow, remove the foliage and store bulbs in a cool, dry and dark site for about two months. If need be, repot bulbs so that the top one-half to two-thirds of each is above the soil. Water and place indoors in a well-lit area. The bulbs should bloom in six to eight weeks.
• Divide and transplant iris during the month of August. Cut back the foliage by two-thirds, dig and divide rhizomes, removing any dead portions. Check for iris borers and replant in a sunny, well drained location with one-third of the rhizome above the existing soil level. Water well.
• August is also a good time to dig and divide daylilies, using a sharp shovel to split the clumps into desirable sizes. Cut back foliage to five inches and replant in a sunny location.
• During dry spells, continue to mow the lawn on the high-level setting.
• Avoid pruning trees and shrubs starting in late August. Particularly hedging plants such as boxwood, hemlock and hollies — since doing so this late in the season can stimulate new growth that will not harden off before frost. If spring-flowering shrubs are pruned now you will be sacrificing next year’s flowers. Delay pruning any tree or shrub until the plant is dormant. Any major pruning should be done in late winter.

And most important as the mercury continues to climb this month, sit back and enjoy the bounty from the garden.

The UT Gardens include plant collections located in Knoxville, Jackson and Crossville.

W. Alan Bruhin

Extension Director