May Garden Guide

  • Set Easter lilies in garden
  • Plant cool-weather crops: lettuce, spinach, chard, parsnip, onion sets, beets, carrots, kohlrabi, mustard, turnips, radishes, peas, parsley, and potatoes in early May.  Soil temperatures should be at least 45 degrees.
  • Plant snap beans, pole beans, sweet corn, and onion plants in mid-May.  Sweet corn planted earlier in the season has fewer pest problems.
  • Inspect for Iris borer larva on iris leaves.  Crush larva.
  • For bigger Peony flowers, de-bud several branches.  Stake before buds open.
  • Set out pansy plants when ground is workable.
  • Dig and divide mid summer and fall blooming perennials before tip growth gets too tall.
  • Plant tuberous begonias.
  • Watch birch leaves for birch leaf miner infestation.  Use sticky traps to monitor emergence of adults to help time spraying with summer oil, Neem extract, or totenone.  Sprays are only effective on adults or larvae before they tunnel into leaves.  Some soil applied systemic chemicals may be effective in controlling larvae after they have tunneled into leaves.
  • Plant tomato seedlings by pinching off lower leaves and placing on its side in a shallow furrow 2.5 inches below the soil surface.  Soil closer to the surface is warmer and will speed tomato growth.
  • Plant strawberries, bush fruits and grapes in mid month.  Pinch blossoms from newly planted strawberries to develop strong plants for next year.
  • Remove faded flowers from spring-flowering bulbs.  Cut off stalks but allow leaves to die down naturally.  Fertilize after blooming with 5 10-20.
  • Plant stored geraniums in well-drained soil after last frost and keep moist.  Growth should begin in one week.
  • Prune spring-flowering shrubs after flowers have faded.  Apply fertilizer.
  • Toward end of month, harden off seedlings of vegetable transplants and annuals grown indoors.  Bring in at night or place in cold frames before planting in garden.
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