Ask a Master Gardener for April 27, 2014
Q: The last couple of summers I’ve had potato bugs in my garden. What can I do about them without using pesticide?
A: Pesticides and crop rotation are unfortunately not very effective with Colorado potato beetles. You may be able to control the larvae when they are small with the bacterium Bacillus thuringiensis (Bt), but you’ll need to spray the plants every few days and Bt won’t kill adult beetles. It can help to grow potatoes every other year, as long as your neighbors aren’t growing them during your off year. It takes some time and vigilance, but hand-picking the beetles and crushing the orange eggs on the undersides of leaves can help.
Read more on potato beetles in Minnesota gardens at extension.umn.edu/garden/ insects/find/colorado- potato-beetles.
Q. Is it too late for me to start seeds this spring?
A: It’s a bit late, but there are plants you can still start this year. To avoid the risk of frost, you don’t want to set most plants out until the end of May in Duluth. (You can get away with about a week earlier if you live near the harbor.) That means you’ve still got four or five weeks, so you could start plants that don’t need much lead time. Vegetables that should be started four to six weeks before planting include broccoli, cauliflower, tomatoes, cabbage, cucumbers, kohlrabi and okra. Flowers include marigolds, zinnias, amaranth, sunflowers, baby’s breath and morning glory.
Start seeds in a sterile mix, not garden soil. Don’t fertilize until they’ve got a couple pairs of leaves.
Even if the seed packet says you can start them in a sunny window, you’ll probably need artificial light to get sturdy seedlings. You don’t need an expensive grow light. A shop light with a “cool” bulb and a “warm” bulb will work. Make sure it’s just a couple of inches from the plant tops.
Keep the seedlings moist. Harden them off the week before planting by reducing water and bringing them outside for a few hours, increasing the time outside each day.
More information on starting seeds can be found at extension.umn.edu/garden/ yard-garden/flowers/ starting-seeds-indoors.