Saturday, 22 October 2016

Winterizing The Greenhouse

Here we are in late October, with winter right around the corner. I pull my jacket in just a wee bit tighter as the girls and I walk about the gardens.  

Whether you have a heated or unheated greenhouse, here are some steps you should take to transition from summer to winter.

Start with a really thorough clean up, both inside and outside.

Wash off all the summertime dust, dirt, pollen, and algae build-up from the roof and walls of your greenhouse, to allow in more of that weak winter sunshine.

Our west coast winters are very, very grey, so all extra light you can provide will be appreciated by your over-wintering plants.

Empty out all plants and accessories from inside the greenhouse, pack away any items not going back in, and then do a really good sweep up.

Clean out corners and crevices really well. 

Use a soapy 10% bleach solution to kill all algae, bacteria and mould spores, followed by a good rinse. I make sure to get the corners, vents, and tracks that the 'windows' sit in, as these seem to be the areas where debris and water accumulate.

We then use a power washer to wash down the walls and floors, removing any bugs, eggs, and built up filmy dust and dirt.

Insulate with bubble wrap or an extra sheet of poly to retain more heat over the cold winter months and save money on heating, too.

This extra layer adds an extra 2 degrees of warmth, so is well worth your while to do, especially with unheated greenhouses.

Leave vents clear as good air flow is essential year round. You will want to open doors and windows, plus run fans for circulation, too. Humidity and condensation will kill/rot your plants faster than anything else.

Run a power cord over to your greenhouse now if you do not have permanent power. You will then be able to plug in a portable heat source during cold snaps, keeping tender plants above freezing, plus run your fan/s to circulate the air and keep down humidity. There are many options for heat sources from small space heaters, to 60 or 100 watt light bulbs, or even strands of Christmas lights.    

Clean up any plant material going back into the greenhouse to over-winter. Cut back, spray all over with insecticidal soap, wash off after 15 minutes with strong jet of water, and re-pot, if needed.

I do not always re-pot now, but often times plants are pretty root bound by end summer, so just top dressing with manure will not keep them thriving through the winter months.

As you cut back your plants, is also the perfect time to take cuttings for new plants in spring.

Bay laurel cuttings take a long, long time to root in...

Wash potting benches, tables, pots and planters.

Set out a few yellow sticky strips to monitor pests. Check your strips often and deal with infestations right away. The last thing you want is to over winter bugs so they come out in full force when you have the greenhouse full of wee, tender, spring seedlings.

Bring your clean plants, tables, pots, bins and buckets back into the clean greenhouse.

Sit back and enjoy your greenhouse before things get crazy busy once again.

Happy greenhouse-ing! 


  1. Replies
    1. Thank you! Is kind of commercial and kind of homey, a cross between the two ; )


Moving Thyme

Sadly, the Nitty Gritty Potager blog is no more... but the good news is that I can now be found at my new blog called the Olde Thyme F...