Here's my growing in a greenhouse guide, more detail as you scroll down.
A Greenhouse will probably be one of the most expensive things you buy for your garden. However, if carefully selected and used properly it will pay for itself many times over and more importantly give you many years of enjoyment.
Types of Greenhouse
There are many different sizes, types and shapes of greenhouse at all sorts of prices from "free to collector" to commercial greenhouses costing thousands, from polythene poly tunnels to aluminium or timber construction, from lean-to greenhouse to apex greenhouse.
The two main greenhouse designs are:
Plastic or glass? Plastic is cheaper, easier to fit, is not brittle and won't break when the kids wack it with a football, but glass lets more light in than plastic and the more light that gets into your greenhouse the better. If the people using the greenhouse are prone to tripping plastic is the best bet.
Which material is best aluminium or timber.?
Aluminium frames are light weight, corrosion free, and require no maintenance. It is also cheaper than wood, but does not look as nice, it also heats up and cools down much faster.
Wooden framed greenhouses need to be treated every few years to protect them from rot, but hold heat better.
What size greenhouse is best for me?
Economy of scale comes into play here, the larger the greenhouse. The less it will cost per square foot of growing space, so it is best to buy the largest greenhouse you can afford and have space for. Once you get hooked and taste the difference, you will have no difficulty in filling it!
How much Work-space will I need?
Your greenhouse interior should allow room for moving around and potting plants.
Have benches to suit your height, to low can cause a bad back, to high you will have to stretch.
Potting benches can be designed to fold down to make more room when not being used they're usually slotted so soil and water can fall through.
You've got to get in and out carrying pots and compost, so make sure the door opens onto a solid path.
What greenhouse accessories will I need?
Guttering to collect rainwater and store in a water butt.
Staging and shelving with slatted surfaces for planting seed trays and potting up and doing other work in your greenhouse. The slatted surfaces are important as they let soil and water through and allow air to circulate more freely.
Ventilation window. It is very important to have a vent fitted in the roof of the greenhouse for ventilation.
There are a lot of companies selling greenhouses, so drive a hard bargain. If an opening vent isn't included in the price, ask for it to be included at no extra cost. As a general rule expect to pay around £500 for a good 6ft x 8ft aluminium greenhouse with a sliding door and vent, £400 for a 6ft x 6ft greenhouse and around £280 for 4ft x 6ft greenhouses. Or place a free advertisement on this site and maybe get one for free.
How much will a new wooden greenhouse cost?
A 8ft x 6ft timber framed greenhouse will cost about £900 make sure it comes with a minimum 10 Years Anti Rot Guarantee and includes Integral wooden staging.
How much will a used greenhouse cost.
You should be able to pick-up a second-hand aluminium greenhouse for about £100 or even free to collect. A second-hand timber framed greenhouse will cost approximately double depending on the condition.
Because aluminium doesn't deteriorate and if you can wait until one becomes available in your area, consider buying (or if you are lucky get it free) a used greenhouse.
There were quite a few small greenhouses offered free to collect, but if you can, go for as large a size as you can fit into your garden. Or two smaller greenhouses and link them end to end to form one large greenhouse.
You will probably need to dismantle it and certainly put it back together. It is a nightmare job especially putting the glass clips in, but you will probably end up with the racking and greenhouse heater too.
It takes a good long day to put a second-hand greenhouse back together, and you might need another pair of hands to help replace missing or broken glass, but it is a cheap way to own a greenhouse.
This time of the year we sometimes have secondhand greenhouses listed here.
Opening the doors of your greenhouse for ventilation allows bees and other Insects to fly in and do the pollination for you. It will also help pollination of plants like Sweetcorn that are wind pollinated.
If you want to give nature a hand try these tips to pollinate your greenhouse plants.
Giving nature a hand pollinating greenhouse plants.
There is nothing wrong with giving nature a helping hand, but opening the doors of your greenhouse allowing bees and other Insects to fly in and do the pollination for you and letting the breeze pollinate plants like Sweetcorn is best.
Choose a level bit of garden preferably out of the way of young children, your greenhouse should receive the maximum amount of winter sunlight available.
You can grow almost any plants you want to in a greenhouse.
Greenhouse gardening is much the same as gardening in the open, just altering it a little to grow stuff under glass. Remember a greenhouse doesn't have to be a "hothouse" unless you are growing a tropical jungle. Plants actually do best in temperatures slightly lower and with a much higher humidity than in our houses. You can control the temperature in small greenhouse quite easily.
You can plant and grow all the plants and more that you would normally grow in an outside garden in a greenhouse.
Early planting in your greenhouse is a good way to make the most of fruit and vegetables you are growing to eat. They should be ready just as prices are still high in the shops. I have listed plants that can be grown through winter here.
Feeding and watering greenhouse produce.
If you have a compost heap a mixture of one part compost, one part good topsoil from your garden, and one part sharp sand, and a little lime is the optimal soil for use in a greenhouse, particularly for growing tomatoes. If you don't have a compost heap bags of potting soil from a local supplier are OK. However, if you want to grow organically check the contents label.
The only time you need to water is when the soil is dry. Over watering will kill your plants.
The more sun your greenhouse gets the more heat the greenhouse will produce. The ideal greenhouse temperature depending on what plants you want to grow is 5 C.
Greenhouse Temperature tips.
Greenhouse heating in autumn and Winter.
How to keep greenhouse winter heating costs down, cheapest way to heat a greenhouse in winter, how to insulate a greenhouse in winter are answered on another page of my site Winter greenhouse heating .
If you are looking for or are recycling a greenhouse visit this page second hand greenhouses
Eight good reasons to own a greenhouse