Viv, SW IrelandPolytunnels
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Hi I'm new to polytunnel gardening. We got one middle last year, size about 26ft long 14ft. across, we put in six different sized raised beds and considering we didnt put anything in until June we were amazed with all the produce we produced. But my main question is:- we live in the SW Ireland so normally its fairly mild down here (although we live up in the hills and had a few nights severe frosts just recently!) sorry, my question is, we have a flap at one end and a double door at the other, just how much ventilation should we be getting into our tunnel? I have the excellent B.Salt's book on tunnel gardening and its brilliant, but I would be grateful if there is someone out there who has tunneled for some years and could give me a few good tips? Most of last year the tunnel was constantly drenched with heavy condensation even during hot days, when we DID have both ends open. Look forward to hearing from you out there?
Viv, SW Ireland
Viv, SW Ireland
hi ive got 2 30x14 tunnels. except for a handful of very hot days i normally only open one end. with both open the through draft sucks the moisture out. i find hot and humid is better than too dry . if there is no condensation on the plastic i feel its too dry in there. the thermometer scales only go up to 50 we often go over that on a sunny summer day, (was in the high 40's today) . during the summer i normally water on sunday morning using a lawn sprinkler on the mains fed hose, given a good soaking they are fine the rest of the week, occasionally in a hot summer they get another soak midweek, i only start the midweek watering if the condensation dissapeers. during the cooler months i use a handheld hose and just water what i think needs it. with the wet spring weve had there seems to be enough moisture in the soil for well rooted plants. now the strawberries are forming fruit and the weather getting hotter it will soon be time to start the sprinkler for the summer.
no doubt somebody else will say i let the temp go to high and dont ventilate enough, but what i do works for me.
no doubt somebody else will say i let the temp go to high and dont ventilate enough, but what i do works for me.
Hi Richard,
As you predicted somebody will contradict what you have said.
My growing tunnel has double doors at both ends and are covered with anti White Fly netting only which allows a flow of air at all times. It is still amazing that the temperatures that can exist, even in January and February, when 90F is achieved on several days.
To me the use of a tunnel is to be able to grow things naturally but cutting out the extremes giving the plants the opportunity to thrive. My tunnels are considerably larger 60ft x 30ft but the one I am talking about is for just the simple vegetables. I do grow Tomatoes in there but they are raised in either the greenhouse of another tunnel.
To raise young seedlings, for example, in an atmosphere that is laden with condensation may work for you but I would suggest the 99% of us would suffer from damping off and other fungal infections.
You will find that with frosty nights that there is no wind and the temperatures in the ventilated tunnel do not fall below freezing point. Even if the temperature does drop below freezing the plants do not have to deal with frost burning which causes most of the damage. Most vegetables are very hardy and low temperatures will not affect them.
The more even a temperature you can maintain the better and to attain this I feel that good ventilation is absolutely essential.
If you could maintain the temperature as near that of a mid May day your plants will thrive.
JB.
As you predicted somebody will contradict what you have said.
My growing tunnel has double doors at both ends and are covered with anti White Fly netting only which allows a flow of air at all times. It is still amazing that the temperatures that can exist, even in January and February, when 90F is achieved on several days.
To me the use of a tunnel is to be able to grow things naturally but cutting out the extremes giving the plants the opportunity to thrive. My tunnels are considerably larger 60ft x 30ft but the one I am talking about is for just the simple vegetables. I do grow Tomatoes in there but they are raised in either the greenhouse of another tunnel.
To raise young seedlings, for example, in an atmosphere that is laden with condensation may work for you but I would suggest the 99% of us would suffer from damping off and other fungal infections.
You will find that with frosty nights that there is no wind and the temperatures in the ventilated tunnel do not fall below freezing point. Even if the temperature does drop below freezing the plants do not have to deal with frost burning which causes most of the damage. Most vegetables are very hardy and low temperatures will not affect them.
The more even a temperature you can maintain the better and to attain this I feel that good ventilation is absolutely essential.
If you could maintain the temperature as near that of a mid May day your plants will thrive.
JB.
hi jb. i dont get problems with damping off , probably because my seeds are either started in the conservatory and only transfered to the tunnels when potted on into 3 inch pots when they are quite sturdy little plants. or the seeds that are started in the tunnels,( sweetcorn , beans, brasicas mainly )are in pots or trays with bottom watering when the tunnel itself is still on the dryer winter watering regime. theres still condesation on the plastic but the air itself is dryer than it is in the summer.
Hi Richard,
The trouble is that not everybody has somewhere else to raise their plants and a well ventilated polytunnel is absolutely ideal. A temporary bench in one corner which, when the need arises, can be shunted out of the tunnel and the area planted up. Even seeds grown direct into the soil will damp off from lack of ventilation. My tunnel coverings are Visqueen anti-condensation grade. Condensation in my tunnels would have caused me great financial losses
so perhaps this is why I am so against it.
JB.
The trouble is that not everybody has somewhere else to raise their plants and a well ventilated polytunnel is absolutely ideal. A temporary bench in one corner which, when the need arises, can be shunted out of the tunnel and the area planted up. Even seeds grown direct into the soil will damp off from lack of ventilation. My tunnel coverings are Visqueen anti-condensation grade. Condensation in my tunnels would have caused me great financial losses
so perhaps this is why I am so against it.
JB.
As with all undercover growing ventilation is important. Even during the winter i will ventilate my tunnel overnight during cold snaps to prevent condensation and use fleece to protect the crops. beware that excessive heat and humidity can be just as damaging as a lick of frost.