Greenhouse borders

[Guest]

I've been having problems with ants and slugs in my greenhouse, and am considering covering the borders with cement. I've not grown anything in the borders for more than 4 years, and all my shelves and benches are propped up on wooden blocks to raise them above the soil. Wouldn't it be better to cover the whole lot with cement? Opinions and experience please! Thanks.

[Chantal]

I'd be loathe to put cement down anywhere in preference to soil. You can get some really good ant boxes from Wilkos. You put them down, the poison is inside and the ants go in then carry it out with them into the nest. It's worked brilliantly for me at home and at work and they're very cheap (£1.99 for 2). Slugs can surely be killed in a beer trap or similar and at a push with slug bait. Cement is a bitch to remove should you change your mind in years to come and want to plant your borders. I would have thought the soil would be better for the general humidity of your greenhouse too. Having said all that, I'm no expert, this is my personal opinion.

Chantal

[richard p]

we had an ant problem a few years ago, was told then that ants like dry soil. we literally flooded the polytunnel and then kept it really moist for several weeks the ants dissapeered. back then we were keeping the soil on the dry side but are now using more water and keeping the beds moister and the problem hasn't reappeared.
in your case it depends whether you want to grow in beds or pots. personally i think pots need more looking after and watering. if you have ants in the soil under the concrete they will find their way up through the smallest crack or joint, so u may not cure the problem, unless u us a plastic sheet masticed to the walls to provide a total seal under the concrete

[Guest]

Thanks for the advice. I use the GH only for propagation of [what seems like] millions of flower and veg plants and hundreds [it seems] were devastated by several large fat slugs - 3-4" long! (Slugs that size aren't interested in beer - I've tried!) The ants made a home in two of my tubs of pepper plants, the only veg I wanted to grow to full size, attempting to produce winning specimins for the autumn veg & flower show. I digress. Here's why I'm leaning toward cement border: I initially propagate many cell trays of flower seeds at ground level on capillary matting on aluminum [sic] foil, on heating cables, on polystyrene, on ground cover, on the border soil -- and I believe that the slugs hid on the underside of the cell trays when small only to be carried high on a shelf to gorge themselves until large on my tiny petunia seedlings! Anyway, the Hessayon Expert book does recommend concrete. The propagation area is about the length of the 10-foot GH, and about 30" wide; I didn't want to buy a table that length, because once seeds are germinated, I replace the heated area with open shelving for growing on. It sure makes a great temp area for germinating, but leaves it open to slugs finding a tasty meal or two... It's hard to see the slugs underneath (I tried). Anyway, thanks for the advice about the ants - and the bit about raising the humidity (I hadn't thought of that). [sic=yes, I'm from the States and can't bring myself to add the extra syllable!]

[Jenny Green]

I agree that you may not solve the ant problem with concrete. A solid border will be a warmer, dryer area for them, which they will love. They could well make nests under the concrete (where you can't get at them), then come in under the door to invest your pots).
I also doubt concrete will solve the slug problem. I speak from experience here. I have several pots of seedlings overwintering under cover on my patio at the moment and they've been attacked by slugs.
Couldn't you have your propagating area up on the shelving?

[Tigger]

The slug problem could be sorted by putting gravel down. No help with the ants though!