Plastic greenhouse

Polytunnels, cold frames, greenhouses, propagators & more. How to get the best out of yours...

Moderators: KG Steve, Chantal, Tigger, peter

Peet
KG Regular
Posts: 21
Joined: Thu Feb 24, 2011 3:39 pm
Location: Herts

Hi All,

I'm new to gardening and I have just bought a plastic greenhouse with 4 shelves. Whilst they are not as good as a 'real' greenhouse can they still do the trick?
User avatar
Primrose
KG Regular
Posts: 8054
Joined: Tue Aug 29, 2006 8:50 pm
Location: Bucks.
Has thanked: 37 times
Been thanked: 281 times

I've got one of these and my first comment is to issue a warning. DO NOT under any circumstances erect it where you can't strap it to a wall or other strong structure. They are incredibly vulnerable to being blown over by sudden gusts of winds, even in sheltered places. I was totally unprepared for how unstable they can be and mine was blown over onto my patio when loaded with trays of seedlings on every shelf. I lost most of them and was not a happy bunny!

We solved the problem by drilling two wall bolts into our house wall, about two thirds up the height of the structure, threading a very long nylon luggage strap through them (bought from Halfords) and putting the strap arouind the whole structure. This has worked a treat and keeps it stable, even in very windy conditions.

Apart from this problem, it has proved very useful for bringing on seedlings although on very cold spring nights when frost is expected, I also drape a couple of layers of fleece over the plastic cover as added protection and anchor it inside the nylon strap. . It has certainly taken the pressure off my lounge & kitchen windowsills which get overwhelmed with seed trays at this time of year.

A couple of other points: Are your shelves divided into two, or are they single shelves? If you're growing taller seedlings it's sometimes useful to be able to pull out half a shelf to let a taller plant on the shelf below grow without restriction. I guess you could always use a wire cutter to divide your shelves in this way if necessary.

Also, in the summer when it's very hot, the plastic cover can melt onto the hot metal tubing structure at the top of the roof. . When this happens, the plastic cover will tear if you try to pull it away. It's worth wrapping a thin layer of fleece or a Jeycloth around the top supports so that the plastic isn't resting immediately on the hot tubing.

Apart from that, I've been very pleased with the facilities this little structure has given me although it's certainly no substitute for a proper greenhouse. If you do need to mend the plastic cover, transparent Duct tape is very strong and does a good job.
User avatar
oldherbaceous
KG Regular
Posts: 13822
Joined: Tue Jan 24, 2006 1:52 pm
Location: Beautiful Bedfordshire
Has thanked: 254 times
Been thanked: 295 times

Evening Peet, i think Primrose has just covered about everything there, but may i just wish you well in your new venture.

It's addictive, though. :)
Kind Regards, Old Herbaceous.

There's no fool like an old fool.
User avatar
Primrose
KG Regular
Posts: 8054
Joined: Tue Aug 29, 2006 8:50 pm
Location: Bucks.
Has thanked: 37 times
Been thanked: 281 times

If you're new to gardening, the one tip which I and many others would probably give, is not to be too impatient if you're sowing either flowers or vegetables from seed, even in your little greenhouse, if they're eventually destined for planting ourdoors.

It's so tempting to think the greenhouse will give you an early start, but as many of us have found to our cost, there's not much point in producing early seedlings if the outdoor nights are too cold or frosty for them to survive when they're planted out. All that happens is that your seedlings grow too leggy, and they never recover and become strong plants after they've been planted out. Better to wait an extra week or so, no matter how impatient you are to get going.
Peet
KG Regular
Posts: 21
Joined: Thu Feb 24, 2011 3:39 pm
Location: Herts

Many thanks for your replies. I'm off to buy a luggage strap tomorrow. My garden is a wind trap and I can imagine watching my greenhouse sailing over the fence into the distance. I planted my tomato, sweet pepper and onion seeds Monday. Every morning since I've looked expectantly in the hope that something has grown!!! Patience isn't my best friend. I think I'm going to like this forum.
User avatar
Primrose
KG Regular
Posts: 8054
Joined: Tue Aug 29, 2006 8:50 pm
Location: Bucks.
Has thanked: 37 times
Been thanked: 281 times

Peet - are you going to be growing your tomatoes outdoors or are you hoping to grow them in your mini greenhouse? I ask because the sowing time will be very different. Tomatoes destined for outdoor growing really shouldn't be sown until mid April because in a greenhouse they'll grow too quickly and it simply won't be warm enough to plant them outdoors until early June when the nights are warmer and all risk of a late frost is past.

If you're going to grow your tomatoesto maturity in your mini greenhouse, do think about growing the "tumbling varieties" which are the low bush sorts designed for hanging baskets or containers. They don't grow more than 12 inches high, don't need staking or sideshooting, and you'll get more of them in your greenhouse. Varieties to look for are Tumbler, Tumbling Red or Tumbling Yellow. The tomatoes are cherry size and very prolific.

When buying your luggage strap make sure you buy one that is long enough to go round your greenhouse. Some of them are only long enough to go round a suitcase. The one we bought came in a pack of two and I seem to remember it was fairly expensive, but it really does the job. A length of plastic covered cable might be cheaper but in a strong wind that could cut into the plastic cover.

You may have to be patient with your pepper seeds. I sowed mine indoors on a warm window ledge 3 weeks ago and they only started peeping through the compost yesterday. If they're outdoors in your greenhouse they will probably take longer.
Last edited by Primrose on Fri Feb 25, 2011 1:20 pm, edited 1 time in total.
Peet
KG Regular
Posts: 21
Joined: Thu Feb 24, 2011 3:39 pm
Location: Herts

Primrose - To be honest I haven’t thought of what to grow yet. I didn’t know about the tumbling variety of tomatoes. I think that’s a good one to try. I was also thinking about trying to grow strawberries in the greenhouse. That way they may stay grandchildren proofed! Will herbs grow in a greenhouse? I really do love these but I don’t fancy the idea of growing them in pots and then having the neighbours cats ‘abusing’ them. Homebase are selling a plastic greenhouse type thingy but without the shelves and wide enough for a growbag. I was thinking of trying to grow the sweet peppers in this. It’s all quite exciting really, although I haven’t seen any green on my fingers yet.
User avatar
Primrose
KG Regular
Posts: 8054
Joined: Tue Aug 29, 2006 8:50 pm
Location: Bucks.
Has thanked: 37 times
Been thanked: 281 times

Peet - you don't say in your profile whereabouts in the country you're located but where I am in Bucks, although I start my peppers & chillis off indoors and then keep them in my mini greenhouse until June, they then go outdoors in large pots against a sunny house wall and stay there all summer. The heat retained in the house wall gives them a good boost.

They crop perfectly well in this environment and reach about 3 foot high so if you keep them permanently in your greenhouse, they could grow taller and limit what else you can grow in it.

Yes, you can grow herbs in there but again most of them do perfectly well outdoors if you can keep the cats away.
Peet
KG Regular
Posts: 21
Joined: Thu Feb 24, 2011 3:39 pm
Location: Herts

Primrose - I’m in Hertfordshire, near Welwyn Garden City. My house is situated so that my garden is in full sunshine from 11:00am till sunset so it does get hot. I never thought of using a wall as a heat source.
User avatar
Primrose
KG Regular
Posts: 8054
Joined: Tue Aug 29, 2006 8:50 pm
Location: Bucks.
Has thanked: 37 times
Been thanked: 281 times

Peet - if you put your hand on your house wall during summer, you'd probably be surprised how much warmth it contains and if you've got a house wall that attracts sunshine from 11 am until sunset in your neck of the woods, you should be able to grow your peppers outdoors against that wall without any problems.
I grow chillies, peppers & aubergines outdoors against the wall. I just line all the large pots up in long drip trays to catch any surplus water and mostly leave them to their own devices once it's warm enough to put them outdoors. They do tend to grow quite quickly, so I use 8" pots and put some chicken manure pellets in the compost before planting them
Post Reply Previous topicNext topic