Hartley Magazine

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

Ventilation In The Greenhouse

In The Greenhouse with Lila Das Gupta

In addition to sharp eyes, a keen sense of smell is vital in the greenhouse. A couple of weeks back I started to notice a damp smell not totally dissimilar to that of a bathroom that isn’t properly ventilated. In addition the soil on top of the pots had taken on a green hue from the growth of algae, so I realised it was time to take immediate action before serious problems started to develop.

Don’t let condensation persist in a greenhouse. Open doors and ventilate, ventilate, ventilate

One’s first instinct might be to heat the greenhouse even further, but in fact the best thing to do is to ventilate, ventilate, ventilate. Damp conditions come about when there is insufficient airflow, so, the solution is to open vents and windows to let in air from outside that will circulate and neutralise over-humid conditions. Since there is still a spring chill in the air and to avoid harmful draughts, start with opening windows and vents just a centimetre or two each day (closing up at night) but open more if the smell persists. It’s also important to watch how you water: remember that if the air is humid inside the greenhouse, it takes longer for the soil to drain off which can lead to problems later on. From my observation so far, it seems better to leave a plant a little on the dry side than to have a soggy sponge waiting to rot your roots.

Given the importance of ventilation, I do wonder why all greenhouse manufacturers offer Louvre windows and other openings as ‘optional extras’ – it’s a bit like selling someone a house with front door and windows as ‘add-ons’.
So, if you’re reading this and you’re yet to buy your greenhouse: make sure you order at least 4 openings in your greenhouse or you will be storing up problems later on. If you can’t afford the vents and extras, then don’t buy the greenhouse! Greenhouses are not cheap. They are a long term investment for those whose passion is gardening. Like an expensive pair of shoes or a beautifully cut jacket that you wear again and again, if you spread the cost over a ten or twenty year period, the outlay seems far less painful.

Christmas may seem like a long way away but I’m already wondering how many vegetables I can grow for our family lunch. The parsnips have now been planted out in the allotment, but now is the time to buy some ‘First Early’ seed potatoes and put them at the bottom of your fridge in a paper bag (Do not forget to mark them ‘Do Not Eat!!!’ lest a helpful partner turns them into Dauphinoise.) In late July take them out of the fridge and plant them into pots, bringing the pots into the greenhouse as the weather turns cold at the end of the summer (potato plants are not frost hardy). Give them a fortnightly feed with a weak liquid seaweed feed. If all goes to plan, you should get a harvest for December. Some companies advertise ‘Christmas potatoes’ in their catalogues, so keep an eye out if you don’t get round to buying any ‘first earlies’ now.

As is fitting for Easter I am potting on to the sound of ‘Jesus Christ Superstar‘ released in 1970 by Tim Rice and Andrew Lloyd Webber. I can remember being taken to the stage play as a child. Everything comes full circle in the end: my daughter has just been in a performance of the play for her school Passiontide. Now both of us can’t get the tunes out of our head: a truly modern classic.

  • My greenhouse is so small that it doesnt come with the option of vents – its the door or nothing! Having read your post I did remember to open the door a fraction today.

    Your reference to Jesus Christ Superstar took me back to my childhood. My mum was a huge fan of the musical and used the play the album over and over. I suspect I know all the words.