Posted: 17/02/2017 at 10:20
Missclarech, Hello Clare and welcome. Ask as many questions as you wish you will always get an answer from the nice people on this board.
Over the years I have had a few Green Houses and found by trial and error the best way is path up the middle and a lining with pea gravel spread about six inches or more deep, Puncture the lining with a garden fork to allow some slow drainage though the idea is to hold some water to moisten the air. I did away with soil in the greenhouse because it had to be dug out and replaced at least every two years, some will disagree but my findings were it lost its goodness and the plants suffered.,
Orientation. Which way will it face, my main section is south facing, this can mean how much light heat sunshine you get and when, south facing is maximum light and sun. The north side has permanent staging with a sand bed I can heat for seeds, the underside allows me to store pots of plants I am bringing on before they go in the cold frame. The South side I grow tomato's peppers etc in pots, the roots go into the gravel and I keep the gravel wet. In Autumn I erect a staging for the winter to bring in plants in pots, grow some cut and come again greens and a few Alpines. Root Vegetables are seasonal and grow outside apart from some potato's grown in bags for Christmas so forget roots in the Greenhouse. Salad crops can be grown out of season but out side in summer, it gets way too hot for them in a GH. Over the years shelves have been erected high up to put pots on, there never seems to be enough room in even the largest GH. This is how I learned to work a green house over many years of trial and error but your needs may differ. feel free to ask more.
Snails and slugs will get everywhere even into your greenhouse, you have to be strong a tin with domestos and water, a torch and go pick them off and drop them in the tin. Keep the floor clear of old pots and things they can hide in during the day. In Autumn when I deep clean the green house spraying the gravel with a mild disinfectant kills any thing hiding. Hope this helps.