is this a good idea?

[frannie]

having taken all your advice, and decided to hide at least half my weeds under black plastic this year, i had one of those "light bulb" moments  - instead of trying to plant through the plastic (i think the bed of tangled grassy rooty stuff would be too thick) i thought of putting down some gro-bags on top of the plastic and making little mini poly tunnels to grow tomatoes and stuff.  i thought they might help hold down the plastic sheet. and i could dig in the gro-bag stuff when i take off the plastic.  it sounds too good/easy to be true, though, so there must be all sorts of catches to it...  are there???

[frannie]

[Jesse]

Frannie I thought about doing a similar thing because I also have a section of my plot that I don't plan to dig over this year. But I decided against it because the growbags will need watering more often and depending on how many you buy it could work out quite costly. But I don't see why, if you're prepared to water more often and buy the growbags, the idea will not work. I have decided to, rather than digging over the entire section, keep the black sheeting over the section, then dig planting holes through the plastic and fill with good soil, then plant into the holes. I can't plant without digging planting holes because I also have a mass of roots etc in the way. The plastic should act as a mulch and help to conserve moisture. I wonder if spreading horse muck over the rest of the section, not including the planting holes, but under the black sheeting will help, it should heat the ground and at the end of summer I should have a good soil to work with.

[Ceri]

just thinking aloud - could you cut a just-smaller-than-the growbag hole in the black sheet - plonk your growbag on top and grow in that.  The theory being the roots would be able to go deeper, the growbag compost will act as an anti-weeds mulch and if any weeds did get through it would be much easier to weed a grow bag size area.  Any thoughts?

[frannie]

thanks guys! i am a bit put off by the cost of the gro-bags, i must admit, but i thought it would be one way of using the ground.  i hadnt throught about the extra watering though, which might present problems.... perhaps i'll try making gro-bag size holes in the plastic, and working those - but wont that defeat the object of coveriing the ground with plastic ??? - or doesnt it matter??? d'oh, i wish i knew a bit more!!!

[Columbus]

> could you cut a just-smaller-than-the growbag hole in the black sheet - plonk your growbag on top and grow in that. <

Hi Frannie and Ceri,

Is that like ring-culture for tomatos? does that work?

my local pound store has bags of compost for .... you guessed it ... £1  ;D
If you have a similar store that might be all you need to get started if you have a high value crop ?

Best of Luck, Col

[diver]

Ive got a similar problem and I have scrounged some deep polystyrene boxes from a local restaurant that has veggies delivered in them....and lined them up and planted strawberries in them, and I did wonder about planting carrots the same way..but I am worried that the boxes might not be deep enough...how deep do they need to be for carrots....sorry to be thick but I am new to this

[Ceri]

Hi Columbus, I haven't tried ring culture tomatoes, so I don't know, but I guess so - I was just thinking of a way to keep most of the ground covered, while allowing the roots of the plants greater depth into the main soil.  Once the roots get down into the main soil watering shouldn't be too much of an extra problem, and if you make sure the edges of the growbag are higher than the soil bit the rain should run into, rather than out of, the bit where the plants are.

[john_miller]

If Frannie has a problem with a mass of grass roots (which I presume are couch rhizomes) then cutting holes in plastic sheet to allow tomato roots to go deeper will probably allow the rhizomes to come up and develop blades and will be very difficult to pull up- they could well infiltrate the bag before you see them. They will come right through plastic sheet if it isn't heavy duty enough, that would include uncut gro-bag plastic.
Divers-what about round/stump rooted carrots?

[frannie]

i was just getting really excited about the possibilities (thanks for all the suggestions, by the way - i like the one about the veggie boxes :)) - and then i read the bit about the couch grass putting shoots up even through the black plastic  :'(  how heavy duty should the plastic be? i'm going to have rhizome nightmares now!

[Ceri]

I used a roll of viscreen - which is used as damp proof membrane and nothing has got through that.  I'm not sure but I think you can only buy it by the roll, which is about 40 quid, for a roll 2 metres by about 40, which is huge.

[john_miller]

As I mentioned recently elsewhere if you use clear plastic you can create a stale seedbed, it is not completely necessary to use black plastic. Growers who have plastic tunnels probably have to pay to dispose of used skins (I know I do) and many, like me, may be glad to have someone take old skins off their hands for nothing. This plastic is very heavy duty and would be impervious to couch or other perennial weeds. Are there any growers using tunnels in your area?
If you do use clear plastic you could always cover it with some light impervious material if you still wish to keep the soil shaded.

[diver]

thanks ,I have just bought some short stumpy carrot seeds which I will put in my polystyrene boxes...I just need to sort them out into little seed trays now.   
I asked a builder who was working on a large building site for some visceen for my allotment and he cut me about 5 yds from the role, so if their are builders in your area try asking

[frannie]

thanks for all the advice. i shall be off to buy my viscreen at the weekend - havent seen many polytunnels around my area - they might all blow away as its a bit breezy down here by the sea!
diver - i have seen globe carrots that might fit in your little trays.
ps  i have always used carboard egg boxes to sprout flower seeds - was intending to use them for my first time veggies as well. are they likely to be ok for veggies?

[abarton6]

Viscreen: I just called a building centre to get a price - its about 46 pounds plus VAT for a roll 4m x 25m.

I said I wanted to use it as a weed suppressant on an allotment and the guy on the phone said he thought it was not suitable as water will pool on the top of the sheet and also that any areas exposed to sunlight will decay and rot eventually.

I said I didn't want to get the rolls of weed suppressant sold in garden centres as they are very expensive for small rolls.

Any thoughts re: water pooling on the surface and rotting rates ??

AL

[john_miller]

Even UV inhibited plastic (which is what is used on plastic greenhouses) will break down eventually, it just lasts longer.
Water puddling on plastic is inevitable. I'm not sure why the guy thinks this is problem. It's unsightly, especially when you find bloated, drowned worms in them, and should be minimised for that reason but shouldn't harm plants. It would also help weigh the sheet down in strong winds!

[sandersj89]

Viscreen: I just called a building centre to get a price - its about 46 pounds plus VAT for a roll 4m x 25m.

I said I didn't want to get the rolls of weed suppressant sold in garden centres as they are very expensive for small rolls.


AL

If you want a cheaper source of landscape fabric have a look at Kays Horticulture.

http://www.kayshorticulture.com/

The on line catalogue is very un friendly but you will find fabric in Catalogue 1 page 24 and page 26.

Prices are pretty good and service is fine.

Jerry
(No connection other than a happy customer)

[Ceri]

It does pool - the only problem I've found with this is it makes moving it around difficult - and slightly soggy - work.  If you mound your beds slightly the water should run off.  Viscreen isn't cheap as you've found out - but I find it a godsend - I've been using it for over a year and it hasn't gone brittle or started to break down yet - I reckon three years is the minimum wear I'll get out of it. 

[frannie]

well, ive burnt my bridges now! just spent 42 quid on a roll of the black stuff - its going down!! you're right john, the water will help to weigh it down.  i;ve also got a few pallets to hold down the edges until i decide whether to invest in gro bags or not - i'm such a sitter on the fence! even if i just smother the ******* couch grass and dont have to look at it while i'm digging the rest it'll be worth it.....

[faerie9]

I've got black plastic on mine - only been down a few week tho (bought it 2 months ago :o :o )

I went to the local tractor shop - they are fantastic! Got 8 x 25m black plastic sheeting for £20. Its the stuff they bale hay up with and isn't as thick as I had thought but it seems to be ok at present... I haven't had a peek underneath yet (and yes, I have pools of water too!)

[frannie]

i'm determined not to look under it till next year! maybe not even then!!! :)  wish i had a tractor shop to go to!