Hartley Magazine

All the latest news, hints, tips and advice from our experts

Preparing your greenhouse for Autumn

Dirty windows prevent light from reaching your plants - Sept 2016
Dirty windows prevent light from reaching your plants

It’s that time of year again, time to venture into the hot September greenhouse and start preparing for the colder weather to come. Soon you’ll be bringing in all the plants that have spent the last few months outdoors. But before you do that, you should make sure that everything in the greenhouse is clean and working well.

A major task is cleaning the windows, both inside and out. I use a long-handled sponge and squeegee to reach highest panes. Elsewhere, I generally use a store-bought glass cleaner that contains a little ammonia to help keep insects at bay. It also leaves the glass crystal clear.  Important for winter sun to shine through and benefit your plants the most.

While you’re cleaning the glass, make sure that other things are in good working order. Check the door and window hinges and oil them if needed. Check your automatic window openers and apply a little oil or grease on them, too. Also repair any holes in screens that insects can pass through.

Now’s the time to check your heating system. Turn it on to see if it heats properly. One year I waited until the first frost to check my greenhouse heating system, only to discover that I needed to order parts, which would take several days to arrive. Fortunately, we had a bit of Indian summer during the wait, but don’t count on that. Unexpected periods of early, prolongedcold can take a toll in a greenhouse with a nonfunctional heater.

Spray early to get rid of whitefly - Sept 2016
Spray early to get rid of whitefly

Once your greenhouse is in tip-top shape, turn your attention to your plants. Citrus and other trees may need to be sprayed to
rid them of ants, aphids, whitefly, and other cling-ons that can infiltrate your greenhouse. Also be sure to check under the rims of pots to remove any snails or slugs that would be happy to winter-over in a warm greenhouse with plenty of vegetation to munch on. Now’s the time to start cutting back on fertilizing your plants, which need less food as nights get longer. It’s also the time to trim off any dead or yellowed leaves to keep them from dropping in your newly cleaned greenhouse. Remember that you don’t need to prepare all your plants at once. With more than 200 potted plants to move into my greenhouse at summer’s end, I prepare and move just a few at time. That way my back doesn’t complain too loudly and everything still gets into the warm before frost.