End of the season gardening

Julie Weisenhorn, Extension Educator - Horticulture
University of Minnesota

examine_leaves.gifMinnesota gardeners are very good at flexing with our changing weather. Many love the onset of fall with its brightly colored leaves, crisp apples, goofy squash and global pumpkins. Days are lovely - warm, breezy, sun-filled - perfect for noodling around in your yard. On the other hand, night temps can dip into the 30's and bring frosty mornings. This swing of the gardening pendulum can make us anxious about those last tomatoes still ripening on the vine, our beautiful Genovese basil, the annual flowers still blooming, and our houseplants that have been thriving out doors all summer. Relax. Here are some actions we can take as gardeners to get our plants through this transitional period while we prepare for the winter ahead.

  1. Frost advisory? Move plants into a garage or drape old sheets, lightweight tarps, and blankets over tender plants like annual flowers and vegetables, containers, tomatoes still on the vine and houseplants you haven't prepped yet for the indoors. Floating row covers (available at garden centers and nurseries) can be used for larger plantings. Weigh down edges with bricks or boards.
  2. remove_debris.gifHarvest what you can as soon as possible. Preserve by canning or freezing. (U of MN Food Safety Canning and Preserving). Dry or freeze herbs like basil, cilantro, and thyme. Make pesto and freeze in single serving containers. Plants like kale and cabbage can take the cooler weather, so no need to protect them.
  3. Give houseplants special attention before bringing them indoors.
    • Examine houseplants well for insect pests. Look on the undersides of leaves, leaf nodes and in the crotches of branches.
    • Remove plant debris from the soil surface. 
    • Wipe off leaves with a damp soft cloth. Spray off smaller plants in a sink and larger plants in a shower. 
    • Re-pot with fresh soil to reduce / eliminate pest issues.
    • Wash pots with 10% bleach solution. Scrub off algae, fertilizer salt stains, insect egg masses and nests. Provide a large enough saucer for plants to drain adequately.
    • potted_herbs.gifMany plants will experience leaf drop when brought indoors and into a different set of growing conditions (lower light, drier air, warmer temps). Prune houseplants for better form and to reduce the amount of foliage the plant is required to support. 

Gardeners can extend the growing season as well by using cold frames, hydroponic tables, and potting up herbs to bring indoors. Cold frames can be built or purchased as kits online and at garden centers for a wide range of prices. Locate cold frames in sunny sites directly in gardens. Plant crops like lettuce, arugula, chard, spinach and radishes now for fresh eating when the snow is flying. Grow plants indoors for year-round fresh food. U of M faculty Tom Michaels developed a hydroponic salad table for indoor use. It can be moved outdoors during the warmer months. Other alternative growing methods include growing walls and window farms. Or simply dig up a favorite herb, pot it up and place it a sunny window for fresh herbs through the cold winter ahead.