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By Linda Peacock, Master Gardener, SCMG

Now is the time of year that your vegetable garden is showing a bit of space.  You have run out of peas, green onions, radishes, spinach, and lettuce and you are anxiously waiting on your carrots, cabbage, tomatoes, peppers, onions, garlic, etc.  Some of the later crops may indeed use some of the extra spaces as they grow to their full potential, however, there is always room to pop in a few more seeds to round out the season.  The cool weather crops that have already been used up or have bolted in the warm summer weather can be grown one more time before the frost comes.  The days are becoming a little shorter, less warm and the evenings are nice and cool – just how they like it!  They will germinate quickly in the warm days and thrive as they mature with the cooler weather.  Radishes and green onions do not take long to grow to their usable size and there are many varieties of greens that you can grow in a short season.  The nice thing about growing some of these greens at this time of year is that any pests that usually feast on them are no longer around, so you get to them first.  And there is nothing nicer than those baby leaf greens in a salad twice a season. Try different kinds than you grew the first time and compare which are your favourites. Buttercrunch is a lovely lettuce that grows quickly and has great flavour. Many different greens such as Arugula, Mache, Tatsoi, and Mizuna also grow quickly and add interest to any salad while their thicker leaves handle a bit of frost.  

Here are a few things to remember:

  • May 11 and Oct 1 have been the average frost dates in Ontario from 1976-2005   
  • This give us roughly 130-165 frost free days to play with depending on where you live
  • Check the newest zone map at to check your proper dates
  • Cool-season crops do best when the air temperature is 5-20°C (heat stops growth or induces bolting), some can maintain at 2-4°C 
  • Warm season crops grow best when the air temperature is 15-30°C
  • Warm season crops are best planted before days shorten to 10 hours or less when growth slows dramatically
  • Don’t be afraid to plant things close to avoid weeds
  • Use tall crops to shade tender greens
  • Don’t forget the spaces in your flower beds, that really fools the pests!
  • You can only eat so much, only grow extra crops of those vegetables you eat a lot of.  A 4’ x 4’ square garden will produce enough salad vegetables for one person all season using the “square foot gardening” method
  • Use pots that can be moved or covered in case of frost, there are many bush varieties of many vegetables even peas and beans that can be used

There are many methods to help us extend the harvest season that may need a little more planning than planting a few extra seeds at the end of summer:

Raised beds are warmer and they are easy to use with floating row covers and poly tunnels. Floating row covers let water, air and 85% of available light through.  They give frost protection and slow water evaporation from the soil while they keep out pests.  They do need to be removed before the plants need to be pollinated. Poly tunnels or hoop houses provide more heat than row covers, however, do not allow any moisture in. The ends can be kept open to allow for air circulation and pollination when the threat of pests is gone. They enable growth and harvesting well past frost dates.

Cold frames can protect plants to approximately -4°C, extending both the growth and harvest season. They are very effective in hardening off seedlings.

Succession planting– Start seeds a few weeks apart so that you can enjoy a more continuous harvest (this also fools some pests).  Grow different varieties of the same crop that have varied maturity dates.  

For now, go throw a few more seeds in the garden spaces for fun and enjoy your garden for the rest of the season.  It will be soon enough that the frost will come!  That will be when you can while away a few months looking at pictures and creating garden plans.  Don’t forget the cheapest most informative resources we have are seed catalogues (until you start ordering of course I myself tend to get carried away).  

A few of my favourite resources – The Organic Home Garden by Patrick Lima, Year Round Vegetable Gardening Niki Jabbour,  Square Foot Gardening by Mel Bartholomew