Autumn gardening - October greenhouse

By now the cooler weather will be back with a bang, so I hope you used September to get your greenhouse ready to protect your tender plants. You can help insulate your greenhouse by surrounding it with bales of hay or other outer foundation covers like branches rested against the outer glass to create an insulation layer of 'dead' air between the outside wind and temperature and the glass. Don't forget though, that too tightly-sealed a greenhouse is a disadvantage to the plants inside, they will not get the necessary carbon dioxide and air circulation to prevent condensation and that they can succumb to mildew or other diseases of the damp, so make sure any external layers you had will not interfere with your circulation fan and base vents. Now is the time to test the heating system and make sure everything is in order and if you still have whitewash or other forms of shading on the greenhouse, you need to get rid of them now, as the plants inside will need all the light that they can get to thrive through the winter.

Before each plant is to be brought into the greenhouse, prune it back by about a third and check it over carefully, removing any insect pests or diseased or deformed leaves. You can repot plants into new mix if the soil seems crusty and heavily compacted, or pale as it probably won't have enough nutrition to help the plant through the winter. Once all tender plants have been removed from your garden, you may want to consider sowing a ground-cover crop of green manure - this should be a nitrogen-enriching legume, such as clover, vetch or rye and must be turned back into the soil before it can flower.

Assuming your tender plants are now all safe, you may want to turn your attention to your bulbs - water lily bulbs can be over-wintered in the greenhouse. Remove them from their soil, wash them and remove any diseased areas, and place in a clean plastic bag half full of moist sand. Store at about 50 to 55f degrees.

October greenhouse photograph by MarilynJane, used under a creative commons attribution licence