[alanb]

Just bought some of those bags for the greenhouse so I can use the concrete floor space. I am not sure what to use as a growing medium.
I want to grow early veg. followed byToms and salads and possibly cues.
any suggestions please

[LilacSandy]

Ordinary bags of compost will do fine, however if you have some of your own compost then put this at the bottom of the bag and then cover with the bought compost.  This will help stop any weed seeds growing from your home made compost, add extra nutrients, and cost less.

[Auntiemogs]

I agree with LilacSandy and adding some manure to the mix will help if you don't have any home made compost.
I use a large plastic pot with the bottom cut out to add depth for toms and it works for me.

[devonbarmygardener]

Growpots are really good for growbags although as was said before, buckets with the bottom cut out are as good to give god depth.

[mumofstig]

You're talking about something like this, I take it?
http://www.unwins.co.uk/greenhouse-gro-beds-pid4289.html

I would add some soil, or soilbased compost to give the mix some 'body' 

[JayG]

For the last two years I've had my greenhouse I've used full-sized bags of MP compost laid flat and used like growbags. Worked quite well but the plants needed regular liquid feeding almost from the word go and it might have been helpful to have added some dry general purpose fertiliser to the compost first (bit impractical without ripping the bags open first though.)

This year I'm making floor-standing planters out of old pallets which I'll fill with nutrient-enriched MP compost - Mum's idea about adding some soil to give it more body is probably a good one, although it won't be my garden soil which is too sandy to be of much help!

Almost anything you do will be better than using those cheapo skinny little growbags! 

[compostqueen]

The growbags from the allotment shop are much more generous and filled with decent stuff, and at the right price 

[mumofstig]

Trouble is - we don't all have an allotment shop 

[compostqueen]

I bet there's one pretty close by.  You can join any allotment association shop for a few pounds 

[snowdrops]

I've bought those for this year too.I will be buying grow bags & tipping it into the bags,then I've got those plastic pots that have a large rim that you water through,it will all stand on the grow bag trays I already have but I'm going to raise them up off the soil this year.

[Amilo]

You're talking about something like this, I take it?
http://www.unwins.co.uk/greenhouse-gro-beds-pid4289.html

I would add some soil, or soilbased compost to give the mix some 'body' 

The bags look very much like the bags that sand and stoned are delivered in for the building industry. An observant person could find these bags for free as they are a use once only item for the building trade.

[Joss]

I tend to use grow bag's from Aldi , My green house floor is concrete so i asked a friend of mine if he could get me some old pallets and i have the bags on them , I grow salad ,and courgettes in them .

[Amilo]

For the last two years I've had my greenhouse I've used full-sized bags of MP compost laid flat and used like growbags. Worked quite well but the plants needed regular liquid feeding almost from the word go and it might have been helpful to have added some dry general purpose fertiliser to the compost first (bit impractical without ripping the bags open first though.)

This year I'm making floor-standing planters out of old pallets which I'll fill with nutrient-enriched MP compost - Mum's idea about adding some soil to give it more body is probably a good one, although it won't be my garden soil which is too sandy to be of much help!

Almost anything you do will be better than using those cheapo skinny little growbags! 

Oh! I wish I could swap a ton of your sandy soil for a ton of my brick making clay!!!

[mumofstig]

In a dry year, you wouldn't want all the watering it needs, believe me   

[JayG]

Oh! I wish I could swap a ton of your sandy soil for a ton of my brick making clay!!!

If I could I would (seriously - I must be quite a rare orangutan because I actually peer into skips as I pass them looking for nice heavy, greasy lumps of clay rather than other "treasures"!)