Mold, Seeds, Bugs and Stressed Plants -Outdoor Farms; Winter is coming!

According to, Northern Califorinia is in for a cold wet winter. Turn up your heaters and fix your light bleeds and don't forget about the moisture....

Things to do to prepare your greenhouse for winter:

1. Insulate, Insulate, Insulate!

2. Wrap your pipes to prevent freezing. In empty bays, flush your irrigation system and test your water pressure. Increase water pressure by purchasing a booster pump or decrease pressure by changing out your heads and lines. 

3. Wash and rinse your outtake vents and blowers thoroughly. Buy some UV lights - research which types are best for your environment.

4. Roof repairs - do this asap - the rain is already here and it's going to get worse.

5. Check drainage and remedy if your plants are sitting in water for more than 15 minutes. Make sure you have good drainage for your plants, level your floors, use trays that drain. In old greenhouses diseases can come from below as well as above, make sure you clean your groundcover and repair any holes. 

6. Get to your farm before the sun comes up, leave at dusk and track the lunar cycle. The moon has a lot to do with soil expansion and gives you clues on how to treat your plants throughout the month. 

7. Winter is a good time to build your nursery, clean up and prepare for spring. 

8. Adjust your nutrients and reduce your pesticides.  

9. Fix your lights - make sure all bleeds are repaired.  Any lighting changes can affect your plants flowering time. Stressing out your plants can cause hermaphrodites, mold and  

(more tips from below) 

10. Repair broken glass and ripped polycarbonate. If left unfixed, these are places that can leak warm air outdoors -- a counterproductive occurrence in a greenhouse that should remain cozy for plants.

11. Caulk around the foundation of the greenhouse wherever gaps occur, however thin or small. Caulk in other places, such as around windows, as necessary. If a gap is too large for caulk, apply foam sealant. Besides keeping cold air from entering, caulking also keeps out pests.

12. Tape translucent bubble wrap to the inside walls, windows and ceiling of your greenhouse. This novel insulation lets light in while helping to keep the inside of the greenhouse warm and reducing heating costs. In spring, you can remove the bubble plastic and store it for the next winter. It lasts for three to four years.

13. Wash out empty pots and trays that you plan to use for moving outdoor plants into the greenhouse in winter. A spray of water can kick out pests that would otherwise move into the greenhouse and infest other plants.

14. Set up a two-speed fan on the low-speed setting. This provides appropriate winter ventilation for a small greenhouse with less than 5,000 cubic feet of air. Add a second fan on the low-speed setting for a larger greenhouse.

Things You Will Need:

  • Caulk
  • Foam sealant
  • Bubble wrap, 1 inch thick
  • Hose
  • Two-speed fan


  • Do not shut all vents when caulking and closing up your greenhouse, as greenhouses need fresh air no matter what the season. 

Enjoy your winter and stay warm.

WATCH More and GET Buzzed on WeedTV! Sign Up - It's Free!

If you have an interesting story please let us know at

Like us and Subscribe on IG, FB and Twitter

Cannabis Bugs Spider Mites Marijuana Diseases Powdery Mildew Mold and Mildew