Grow Your Own Magazine

Our polytunnel is new from this spring; it is producing well and we are very happy with it..
I have installed an automatic spray watering system from First Tunnels ( bought with the kit ) and a timer from Lidls.
I have initially set the timer to water the tunnel on a daily basis at 09.15 for a quarter of an hour, which seemed fine until we went on hols for a week. Coming home we found that many of our strawberries had gone mouldy even though we had left, what I thought was , plenty of ventilation. Some other plants such as peppers didn't look too happy either.
As the timer can be programmed in many ways , should I alter it to "rain" less often but for longer ? or even one minute every hour ?
The longer period would seem more natural as even here in Scotland it doesn't rain every day
Advise or experience on this would be much appreciated.

I am using a similar system. It goes on for 15 mins at about 6pm. So far, so good. But the moudly strawberries might just be a co-incidence - I had that problem earlier in the season before the auto watering was set up, it seems that the 'corners' of the tunnel can be very difficult to ventilate.

Put a few jam jars around, and see how many "inches" of water the various parts of the tunnel are getting?

I think ths can be a problem to do with the weather 'outside' all that damp around this year.

I have totally BANNED my husband from watering our tunnel at the moment, it seems so damp in there - outside temperatures are so low - its a gamble to have the doors open to vent and still keep the temperatures up inside.

I appreicate that the tomatoes might not like this erratic watering - but a neighbour of mine who grows the most amazing veg says he seldom waters in his tunnel during bad summers and he doesnt get blight in there either (I did last year) Incidently the same neighbour says overhead watering in tunnels causes more problems and that irrigation pipe type watering is better (please dont shoot the messenger!)

Was someone opening the doors on warm days?

"please dont shoot the messenger!"

I reckon your neighbour is right! Shoot me if you disagree ...

The thing you need to remember is that different plants have diferents needs when it comes to watering, temperature and humidity.
Whilst you cannot change the temperature in one part of the tunnel (unless you put in a dividing screen) you can adjust the watering by using different methods. Overhead watering is alright for some crops but not for beans etc where the flowers produce the fruits and overhead irrigation can knock off flowers before they are pollinated. In addition, during summer, overhead watering in the early evening can mean that water sitting on some larger leaves can lead to scorching.
Plants like tomatoes and cucucumbers need a lot of water (as that is what they mainly consist of) but neither like getting their stems wet -I sink piots beside them and water through those - an alternative is microbore drip feed system.
Other crops such as lettuce may get scorched of diseased if the leaves remain wet for any length of time, so a seeper hose would be the preference for that type of crop ( and for beans too for that matter).
Cucumbers like it humid but tomatoes like it drier - so you try and water the ground round cukes more than round toms - or spray your cukes with a a misting spray daily.
It's all a matter of deciding what you wanna grow, how much time and /or money you are prepared to invest in watering systems and going from there.
Good luck.

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Rat

British by birth
Scottish by the Grace of God

Blog updated Wednesday November 13th

I do a bit of both in my tunnel. I use the overhead watering system for holidays and if we are away for the weekend. I only do 3 mins in the morning and another 1 min at night and find this perfectly adequate. Otherwise I water myself, but I got myself a good sprayhead and so can get into most of the difficult bits of the tunnel and into the roots. Every now and again I might put the overhead watering system on just to dampen things down a bit when it gets a bit hot - HOT? haha, not this year!

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Aerodynamically the bumblebee shouldn't be able to fly, but the bumblebee doesn't know that so it goes on flying anyway.
~ Mary Kay Ash

Thanks for the ideas.
I have now decided to water for one hour every 4 or 5 days and this seems to keep most of the plants happy.