Season Extenders for Gardening

Season Extenders for Gardening

Season Extenders Comes in all Sizes

Season extenders are simple ways that we can extend or lengthen our growing season through various means using different methods, materials or products. The concept is to start the spring earlier and end the growing season later. Some things we may use are row covers (garden fabric), grow tunnels, hoop houses, cold and hot frames, and greenhouses. Every day we see new ideas and products being developed all with the same idea: protecting your plants from the wind and cold.

Depending on what is used and how diligent you are, you can easily extend the season in the north to a year–round garden. The possibilities are endless.

Uses of Season Extenders

  • Spring seedling can be started seven weeks before they are to be put in the ground. Once the soil is warm, you can either start the seedling or grow an early crop of greens.
  • One advantage of growing your seedling directly outdoors is they develop better. There is more light available and they are better adapted to the outdoors.
  • If you use a cold frame it can be placed against the house by a basement window. You seal the area between the window and cold frame. The basement window can then be opened to allow the heat from the house to radiate into the cold frame at night.
  • Another method of generating heat is to use manure or food scraps, leaves, compost or something that will decompose. Cover the area with four to six inches of soil as the top layer. You then plant on top. The heat generated by the warmth of the material decomposing underneath will allow the plants to grow another month or two.

Grow Tunnels and Hoop Houses

Grow tunnels and hoop houses are placed over a garden bed. I use 1.5” PVC pipe. The ends of the pipe can be buried and then you anchor the cover at the ends with clamps. Also, you can bury two-foot lengths of rebar, leaving 10” or so above ground, and then place the ends of the PVC into the rebar. The PVC pipe should be around 8’ – 10’ length for a bed that is four feet wide. The hoop tunnels are coming smaller and are not as tall. Therefore, you only need a short wire that goes across the bed. The height of the hoopa are around two feet tall.

The hoop or grow tunnels can be covered with plastic, which should be tucked in on the sides or held with a piece of wood.  Another option is to roll any extra material and anchor it with rocks.

Fabric Row Covers 

Row covers are great season extenders

They are a special garden fabric that are very popular due to their lightweight nature, ease of using them, as well as being able to store them once the season ends. The material used feels and looks like fabric but is made of a polyester or polypropylene They have some that are of a heavier material and others are of a light material. The lighter weight ones are good for the spring and the heavier ones for the fall. Both allow light, water and air to come through. Place material over hoops or wire mesh and hold it down along the sides the same way as with the hoop or grow tunnels.

Advantages of Row Cover

  • Row covers keep heat in and can easily raise the temperature inside by five to ten degrees Fahrenheit.
  • The thicker ones used in the fall can provide protection for outside temperatures up to 30° F.
  • The biggest advantage is that they help keep bugs out.
  • Vegetables develop faster and the plant leaves will be bigger due to the extra heat. If the broccoli plants begin to form the heads sooner than anticipated, they will not get as big due to the heat. A few warm days and the heads can start to open up. Read more about growing broccoli 
  • See the video on advantages of row covers

Cold and Hot Frames

A cold frame is a structure made of wood, hay, bricks, cinder blocks or some other material that creates an enclosure or square, ending at a 45° angle at the top. The cold frame is facing the south side. It is covered with glass, plastic or Plexiglas. Cold frames are used to start seedlings, or to harden them off before planting them in the garden. They are used to grow leafy crops during late fall or late winter months.

Place them facing the south side in order to draw maximum heat from the sun during the day. There are automatic vent openers’ that can be added to close the opening when it starts to get cold inside or if it starts to get too warms it opens. Hot frames are cold frames with heat.


Heat is needed during the winter months. By placing black 55-gallon steel drums filled with water and stacked two high on the north side of the greenhouse it will keep the temperature inside above the mid 40° F. The greenhouse has to be covered with a double layer of plastic.  Use the area with southern exposure  to grow vegetables.

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Which Vegetables to Plant

Green leafy vegetables do best under low winter light, irrelevant of how much warmth you have.  Any type of leafy vegetable will do fine – either in a greenhouse, cold frame or hot frame. Tomatoes and the like will grow but not go into a fruiting stage due low light conditions. Radishes and some of the root crops will produce but the bulbs will be small.

Season extenders are a great way to lengthen the season. It’s a real pleasure, especially in the late winter, to be able to have leafy greens right from your garden. Enjoy!