When Can I Plant What?

Garden Clippings for April 17, 2021

Warm weather is playing games with us.  February was warmer than usual.  March was warm with very little rain.  It is now the middle of April and we have not had seen frost for two weeks.

Pardon me for being a party pooper, but winter is not behind us.  We may not get snow, but we will get frost.  The traditional frost-free date for Sarnia Lambton is Victoria Day weekend, this year falling on May 24.  When it comes to deciding when it is safe to plant, I suggest looking at the calendar rather than the thermometer.

Onion setts and potatoes can be planted outdoors anytime after the 15th of April.  Onions do not mind a touch of frost. Spring bunching onions will be ready to harvest in mid-June.  Mature onions will be ready in late summer.  Since potatoes are planted under a mound of soil, they will be protected from frost.  Potatoes are fun to grow because a few seed potatoes will soon become a bushelful.

Lettuce can be planted outdoors at the end of April or early May.  If you would like a head start, start lettuce seeds indoors in the middle of April, for planting outdoors in the first two weeks of May.  Lettuce is a cool season crop and wants to be planted early to enable you to harvest before the hot days of July.

Peas can be seeded directly in the ground anytime after the first of May.  If the weather cooperates seeds will sprout quickly, but if soil remains cold, they will sprout only when they are ready.

Cabbage, Cauliflower, Brussel Sprouts and Kale will withstand a light frost and can be planted anytime in May.  If you have the room, start them indoors in April and plant them outdoors a month later.  Alternatively, get the nursery to start them for you and plant seedlings outdoors in May.

Beets, carrots, parsnips, radish and spinach can be planted the second or third week of May.  Sow seeds directly in the ground and do not worry if they get a touch of frost.  Radish will be the first to sprout and first to harvest.  Ditto for spinach.  Beets and Carrots need warm weather to sprout and flourish.

Tomatoes, and peppers are not frost tolerant, so do not be tempted to plant until the end of May or June.  Most gardeners buy transplants rather than starting seeds indoors.  Tomatoes and Peppers are easy to sow indoors.  Start seeds in the middle of April and they will be ready to bring outdoors 6 weeks later.  If the weather is warm, set the seeding trays on the patio outdoors in early May.  Do not be tempted to start seeds too early, for fear they will become leggy.  Tomatoes and Peppers are fine with planting outdoors anytime in late May and throughout June.  If soil is too cold, they will take their time.

Cucumbers, squash and Zucchini need heat and will not tolerate frost.  Plant seeds directly into the soil after Victoria Day weekend.  If you would like a head start, plant seeds indoors in early May.  They will sprout quickly and can be planted outdoors when the danger of frost is past.

Peas enjoy cool weather, and their seeds can be planted outdoors in April.  Beans need warm weather and should not be planted until late May or early June.  For continued harvest, plant new bean seeds every two weeks.

If you are tempted to jump the gun and plant early, you will probably be lucky.  But frost or no frost, most plants will not begin growing until the soil warms up.  I always suggest erring on the side of caution and planting later.  Don’t be afraid that our growing season might be too short.   My friends in Thunder Bay, where the frost free date is 3 weeks behind Sarnia’s, tell me their gardens are just as productive as mine.