Effects of the cool spring, winter crops to sow, spring pests (May 25, 2022]

From Linda Gilkeson:

With night temperatures finally at reasonable levels for tender vegetables, it should be safe to plant squash and tomatoes in most gardens. I am still holding my cucumbers and melons in pots for a little longer, bringing them indoors at night. If you planted out such tender plants earlier and they are still looking OK, that’s great–but if plants are now in poor shape, you might want to get replacements this week while garden centres still have stock. If they didn’t outright die, warmth loving plants that were planted outdoors while nights were still too cool may be looking sadly nutrient deficient now. They might have pale yellow leaves, or in the case of tomatoes, purplish and yellow leaves. The oldest leaves may look even worse—turning brown, wilting or dying back—especially after leaves of some plants were windburned by high winds in the storm last week. In the last several days of warmth, however, any plants with a will to live should be showing signs of healthy dark green new growth. If that’s the case, they will probably recover. If they are still going downhill after this recent spell of warmer weather, then they likely won’t recover. The more robust squash varieties (zucchini and a few winter squash) that I planted outdoors a few weeks ago have taken a hit. Most of my outdoor squash are making a good comeback, but they are certainly worse for the experience. Squash I moved into in larger pots and continued to bring indoors at night are now much larger and healthier than the plants outdoors.

Vegetables that thrive in cooler weather (cabbage, peas, lettuce and leafy greens, root crops, etc.) are finally beginning to grow well, so keep on planting. If you haven’t planted these yet, go right ahead—there is still plenty of time for them produce good crops this summer. There are no heat waves in the long range forecast, but keep in mind that these crops will be the ones that need shading if a heat wave crops up later on.

The soil may still be a bit cool to sow beans outdoors yet and it is certainly to cool to sow corn right now. For beans, soil should be at least 15C/60F and for corn 18C/65F (warmer is better). However, you can certainly get a start on planting those crops right now by germinating seeds indoors. I put several dozen bean seeds in a large container of vermiculite or planting mix and germinate them on bottom heat. They can grow in the container for up to 2 weeks, spending the days out in the sun or in a cold frame and the nights indoors. When bean plants are about 15 cm/6 inches tall, carefully disentangle the roots and plant them out. Corn doesn’t tolerate that kind of root disturbance so plant each corn seed in its own small pot or cell of a seedling tray or egg carton. Both beans and corn might have to be protected from birds after planting: make hardware cloth or screening covers or drape plants with floating row cover.

A note on corn: Because it takes a lot of pollen raining down on the silks of the ears to achieve fertilization, you need a certain critical mass of corn plants. In a small garden, trying to get a corn crop with 6 or 12 plants often fails. With so few plants shedding pollen (it comes from the tassels at the top of the plant), the pollen often misses the ear directly below—especially if there is a bit of wind. This isn’t a problem in a corn field because there is plenty of pollen floating around in every direction. I have found that it usually takes a block of 25 plants for sufficient fertilization to occur. Plant them in a dense block of 5x5 plants, rather than in rows. Even so, some of the kernels at the tips of the ears may not develop because they weren’t fertilized.

Winter planting starts now! Hard to believe, but we are starting into the main planting season for crops to be harvested through winter. The last week of May to first week of June is good timing for sowing Brussels sprouts and for varieties of hardy cabbage that need 120-180 days to mature (check variety descriptions for ‘days to harvest’). I now sow these plants a week or so earlier than I used to allow for the potential loss of some growing days during periods of extreme weather. Plants grow slower in cool weather, with warmth loving plants most affected, but plants also stop growing during heat waves, with cool weather crops most affected. With weather becoming increasingly variable due to climate change, there is likely to be more “no-growth” or poor growth days in the season. You can print out a summer planting schedule for winter crops here: http://www.lindagilkeson.ca/pdf/Linda%20Gilkeson%20Planting%20Schedule.pdf

Roundup of pests du jour:

  • Tent caterpillar eggs hatched late this spring and the web nests are small right now. Mostly they are still feeding on the buds at the tips of branches, where the webs are hard to see. Keep inspecting apples and other fruit trees and prune nests out of trees if you can’t reach them by hand. The earlier you remove the nests, the less damage there will be. Lots of details on tent caterpillars in last years May 24, 2021 message Linda Gilkeson || West Coast Gardening || Gardening Tips
  • The cool weather has delayed development of insects and climbing cutworms are still causing damage in some places: after dark, search for these on plants. Cutworms are big fat caterpillars that curl up in a C-shape when disturbed.

I wrote in detail about the following pests last year so for more info on specific control measures, see my April 25, 2021 message.

  • Slugs, of course, are thriving: use slug baits containing iron/ferric phosphate, go out on slug patrols in mornings and evenings, use slug traps of various designs.

  • Wireworms are ever present, especially in gardens recently carved out of weedy patches or lawns. The larvae are in the soil, feeding on roots. It takes 3-4 years for them to mature and for the adult beetles to emerge from the soil. Potato traps used before you plant are effective in luring them out of the soil.

  • Currant sawfly on currants and gooseberries: keep looking for eggs laid on the leaf veins on the underside of leaves low down in the interior of the plants. If you are seeing leaf damage, look really closely for tiny green worms feeding on leaf edges.

Upcoming talks open to the public:

Saturday, June 4, 1-3 pm. Managing Pests and Diseases in Your Organic Vegetable Garden. Delivered via Zoom for the Compost Education Centre in Victoria. How to identify problems and when to use the organic and non-toxic control methods available to home gardeners. The emphasis will be on simple ways to prevent damage from common pests and diseases, including how to attract beneficial insects that control aphids, caterpillars and other insects. Register through the Compost Education Centre web site: 2022 workshop series – Compost Education Centre

Thursday, June 23, 11-12:30. Resilient Gardens for a Changing Climate. Free. Delivered via Zoom for West Vancouver Memorial Library. learn how extreme weather affects trees and plants, how to design resilient food and ornamental gardens, and how to help plants survive extreme weather. You will also learn the role gardeners can have in mitigating climate change, including designing landscapes to capture carbon. To register for the event: https://westvanlibrary.ca/event/resilient-gardens-for-a-changing-climate-with-linda-gilkeson-virtual/

Republished with permission from Linda Gilkeson’s Gardening Tips. See Linda’s website to sign up for her newsletter, purchase books, access free presentations and identify pests and diseases which may affect West Coast gardens.