Heart of Missouri
Master Gardeners

May Calendar

May - Zone 5

Vegetables

Until mid-month continue planting lettuce, onions, spinach, beets, chard, carrots, parsnips, radishes, turnips, shallots, chives and parsley.
Start squash, cucumbers, melons and okra indoors. Transplant in the garden when all danger of frost is past.
When the soil warms to 60 degrees F. transplant tomatoes, peppers, and sweet potatoes outdoors; harden them off first and be prepared to protect the tender transplants from frost with plastic jugs with the bottoms cut out. Stake the tomato plants as you transplant to prevent root damage.
Keep potatoes well mulched. Keep in mind potatoes do not grow deeper in the soil then they are planted, the new potatoes start forming on the stem node nearest the seed potato and extends upward toward the soil surface. This is the reason for hilling or mulching.
Toward the latter part of the month it is safe to plant sweet corn. Check the maturity days of the sweet corn and sow seed for early, mid-season and late crops.
Direct-sow bush beans, pumpkins and winter squash.
Continue harvesting asparagus through-out the month of May.

Trees & Shrubs & Fruits

Don't spray any fruits while in bloom. Let's protect the friendly flying pollinators. Refer to MU Guide Sheet 6010.
Prune unwanted shoots as the appear on the fruit trees.
Mulch blueberries. If pine needles or sawdust is used it will help keep the soil acid which blueberries need to grow and produce. The proper pH for blueberries is between 4.7-5.2.
Prune spring flowering shrubs after they have bloomed.

Lawns

If you have not applied a pre-emergence broadleaf weed control now is the time to apply a post-emergence weed control if needed.
Mow often enough that you remove no more than a 1/3 of the leaf area at one mowing.
Watch for the appearance of sod web worms.

Flowers

Plant roses and perennials by mid-month.
Water-soluble fertilizer gives newly set-out plants a boost, and slow-release fertilizers continue to give plants in pots nutrients over a longer period of time.
The local garden centers will soon be sold out of top quality plants so be sure to make that list and get started shopping.
Toward the end of the month summer bulbs can be planted, these include caladium, dahlias, Cannes and all tender bulbs.
Remove tulip and daffodil seed pods and let the foliage mature naturally-resist the temptation to cut, braid or tie it back.
Fertilize roses now, and prune away any winter-damaged canes if you haven't already. Keep a small bottle of Elmer's glue near your pruners and dab a bit on the ends of rose canes after you prune them. The glue keeps stem-boring insects from drilling into the soft plant tissue.
Remember---once you notice BLACKSPOT on your roses it is already to late to control this disease. The spore winters over in the soil and mulches and is spread as the wind blows and as water splashes on the leaves. There are a number of good commercial sprays available at your local home and garden center.
When transplanting bedding plants pinch out the very top to promote fuller plants with more blooms.
Direct-seed alyssum, nasturtuim, aster, balsams, clarkias, stocks, marigolds, sunflowers, zinnias and dig and move volunteer violas and calendalus. Fill outdoor containers with petunias, lobelia and other cascading flowers.

Miscellaneous

Birds eat many insect pests. Attract them to your garden by providing good nesting habitats.
Herbs planted in average soils need no extra fertilizer. Too much may reduce flavor and pungency at harvest.
Watch for fireflies on warm nights. Both adults and larvae are important predators. Collecting may reduce this benefit.
We now have something green to add to the compost pile, work in the first grass clippings. This will heat up your compost pile and get it cooking.

Last Updated Tuesday, June 04, 2002

Page Created By Master Gardeners / Internet Masters
Nancy Hendrix and Sharon Young