PolyTunnel Help

[bendm]

Hello to all the grow your owners out there!
At the beginning of last summer I was lucky enough to take on an allotment complete with a walk in polytunnel.
The plot had been left to its own devices for several years and the tunnel was stuffed full of elm suckers from the hedge behind which I duly cleared.
After adding a few bags of FYM to the beds we planted lettuces,tomatoes and peppers and had excellent crops of all these things.
Recently,however,I have been reading that fixed beds in polytunnels can develop all sorts of problems with pests,soil or otherwise,if cultivation continues for a few seasons.They cite changing all the soil in the beds from time to time as a remedy,which sounds arduous to say the least!!!
I was wondering if anyone can enlighten me with regard to this matter and also with general PT maintenance to reduce the risk of P and D problems.
Thanks Ben

[Earthbabe]

Hi Ben. Welcome to the vine. Unfortunately I don't have any knowledge of PTs, not having one myself. However you are sure to find people with plenty of knowledge and advice around.

[nick the grief]

Hi Ben,

If you grow the same family of veggies in the same beds you will run into problems as they exhaust the soil of nutrient & you get a build up of pests. If your polly tunnel os only a small one (8x10) then I would change the soil every 3 - 4 years, If it's bigger than this then I think you would have enough space to just run a crop rotation. Divide your beds into 4 (2 either side I guess) and then grow a differnt crop in each bed then next year move it on one. If you go for opposite beds as well it means there is a two year break per side for extra insurance like this.



Hope that helps

[Snadger]

How to answer a question with a load of other questions!!!

I don't have a polytunnel myself but just wonder if it is hard to re-site them every couple of years?

If it was done during the winter when there wasn't much happening, would it be a viable proposition?

Failing that, is it much effort to take off the polythene or roll it down for a time to allow frost and rainfall to penetrate soil /break up soil and kill bugs. It would also wash away any surface salts build up. Would this along with crop rotation not work?

I would think it must be easier to re-site it as change all the bed soil!

[annie trip]

Hi bendm,very jealous of your poly, after one myself from santa so trying to pick up all tips i can!! Think if you move you need to buy a new cover so makes it dear. Good luck.

[rustylady]

Hi Ben, welcome to the vine

How big is your polytunnel? You are lucky to have one already on site. I have nothing on the lottie, but I do have a small greenhouse at home in the garden.

You do have to think crop rotation in a polytunnel just as you do on the open plot. In greenhouses I usually put plants in pots or growbags (have to, mine is on a concrete base - you could do the same for tomatoes, peppers etc. Otherwise, if the tunnel is big enough you could use a crop rotation system as Nick has advised.

[nick the grief]

How to answer a question with a load of other questions!!!

I don't have a polytunnel myself but just wonder if it is hard to re-site them every couple of years?

If it was done during the winter when there wasn't much happening, would it be a viable proposition?

Failing that, is it much effort to take off the polythene or roll it down for a time to allow frost and rainfall to penetrate soil /break up soil and kill bugs. It would also wash away any surface salts build up. Would this along with crop rotation not work?

I would think it must be easier to re-site it as change all the bed soil!

It's not hard to re-site them but it is a load of hassle Snadger. I wouldn't do it every couple of years I'd wait till the cover needed replacing which can ge anything up to 7 or 8 years, plus you are liable to do more damage to the cover if you keep taking it on & off & as they are around £100 a time (depending on size) you don't really want to damage them.

I don't think it would be a build up of salts thats the problem more of a depletion of trace elements & feeds from the soil & the build up of pests - you wouldn't grow potatoes in the same part of the lottie would you so why grow tomatoes in the same part of the polytunnel.

By rotating the crops & diging on manure like you do in the garden you can get around this problem but you don't need to feed as heavily as there isn't the problem of leaching like in the open ground.

As to the winter, well there may not be much happening outside but you'll get about 12 weeks extra growing season undercover so there may well be loads going on.

[Snadger]

It's not hard to re-site them but it is a load of hassle Snadger. I wouldn't do it every couple of years I'd wait till the cover needed replacing which can ge anything up to 7 or 8 years, plus you are liable to do more damage to the cover if you keep taking it on & off & as they are around £100 a time (depending on size) you don't really want to damage them.

I don't think it would be a build up of salts thats the problem more of a depletion of trace elements & feeds from the soil & the build up of pests - you wouldn't grow potatoes in the same part of the lottie would you so why grow tomatoes in the same part of the polytunnel.

By rotating the crops & diging on manure like you do in the garden you can get around this problem but you don't need to feed as heavily as there isn't the problem of leaching like in the open ground.

As to the winter, well there may not be much happening outside but you'll get about 12 weeks extra growing season undercover so there may well be loads going on.

To be honest, I was just looking at the situation from a laymans point of view ie me!!!! Mine were all questions and ideas & posssibilities to save me from changing bedsoil in the future as it sounded a bit too much like hard work!

[burnie]

I liked the idea that jenni used,raised beds,they've got to be easier to do a soil change if required,it's whats going in my tunnel.

[lilymarlene]

I have a tunnel with a really high quality cover that only needs changing every 7 years or hopefully more.....it is also 10'x15' so there is no room to re-site it anyway. So I have gone down the deep beds route, and change one per year.
But with a smaller one, and on an allotment with greater scope for re-siting, I'd be inclined to move it to a new spot every time it needs recovering. That should be often enough to do the trick. Or if it really is too much bother to re-site it then just leave the cover off for the winter when you have to replace it. You will not be able to use it for a couple of months just one winter in about 5 but that is the only drawback to this method.

[pigletwillie]

We built our own polytunnel this year which has raised beds each side that are 20' long by 4' wide. These were filled with mainly very old manure and a bit of home made compost and soil. A second one is going up this winter and I intend to run tomatoes in one and peppers, chillies and aubergines in the other. These will alternate between tunnels as a crop rotationof sorts.

However if you only have one as long as you feed the soil with manure or compost every year and your crops are still of good quality and yield you should last a good few years without having to change the soil. If you are worried a partial change would be acceptable and much easier to achieve. If you do have raised beds, every time you pull up a plant you lose a bit of soil so they generally need topping up every season anyway which again will reduce to a great extent any problems from occuring.

[bendm]

Poly Tunnel ideas

Thanks very much everybody for your great ideas!!!

[sewer rat]

This thread is scary !! I hope to purchase two tunnels at the beginning of next year and they will be 24' x 60'. There isn't enough soil in Scotland to let me change it !!!!!!

[Snadger]

This thread is scary !! I hope to purchase two tunnels at the beginning of next year and they will be 24' x 60'. There isn't enough soil in Scotland to let me change it !!!!!!

You'll just have to buy another two then, so you can have a four year crop rotation!

[sewer rat]

Now why didn't I think of that !! I probably did but not sure bank mananger would see it my way !!!!