Polyethylene row covers for a head start !



I live in Scarborough Ontario Canada and I will be starting my tomatoes peppers melons etc indoors 1-2 months before planting outside. However I was wondering if I can start planting outside in mid April through the use of perforated polyethylene row covers over my garden beds (the covers will enclosure all areas) ? Our last frost is around May 4th. I am also okay with double layering the covers.

Please advise if this would truly give me a head start or will I just destroy my plants ?

Thank you!!


It’s generally not a good idea to plant outside in April, due to the unpredictable weather during that month.  However, the row covers should protect the vegetables and give a kick start to the growing season – by warming the soil and increasing humidity.  The covers should also help prevent soil water loss, decrease leaching of nutrients from the soil, provide some weed control (although if weeds are present, they will thrive too) and decrease soil compaction.  I’d suggest mulching as well, at least a week prior to planting to enable the soil to warm up. Remember to vent the fabric during the day once temperatures are over 21 degrees C (70 degrees F), so the plants don’t bake.

Consider trying your early planting  row cover strategy on half your tender plants, and keeping the rest inside to be transplanted (as usual) once all danger of frost has passed. Remember too that some vegetables do well in cool weather – e.g., spinach, lettuce, beets, peas, radishes (lettuce and peas like warmer soil than the other vegetables), so might be good options for you to grow.

Others have asked a similar question in the past.  See  Ask a Master Gardener. Growing vegetables in April in Toronto.    Note that the last frost date in the Toronto area is considered to be around May 11-20; you may live in a warmer microclimate in Scarborough, but I’d suggest that you check.  See also Growing Urban Vegetables: A Toronto Master Gardeners Guide, which provides suggested date ranges to start sowing/transplanting vegetables outdoors in the spring.

It would be a good idea to read about row covers – which have both advantages and disadvantages – before going ahead.  Here are a couple of good places to start:

All the best with your veggie crop!