What You Can't Grow
Being self-sufficient is a fantastic lifestyle choice, as you can grow most of your fruit and vegetables, forage for wild greens, mushrooms and fruit, and even keep your own chickens and other livestock. However, there are some things, which you can’t grow without a heated greenhouse (which is expensive to run), and others, which you cannot grow at all.
Rice, Tea, Coffee and ChocolateMany crops that are grown abroad require certain growing conditions to thrive, which are specific to that area. These growing conditions include a high altitude, humid conditions, or a particular type of soil. Rice, for example, normally requires a wet soil and a humid environment.
It is possible to grow it in a bucket in a heated greenhouse, however the plants will die back in the winter due to lack of light and this can happen before the plants have flowered and gone to seed, producing the rice grains you are growing them for. It is much easier to buy (or swap) rice in bulk instead, and concentrate on the crops you can grow.
Similarly, tea and coffee are difficult to grow in the UK. Coffee requires high altitudes to grow, and tea requires even temperatures throughout the year, preferably with wet summers and dry winters (the opposite of the warm, dry summers and cold, wet winters of the British climate).
The cacao (cocoa) tree grows wild in the Brazilian rainforests, and is grown in plantations as near to the equator as possible to ensure the seed pods produce the best possible flavour. Therefore, even if you managed to grow a cacao tree in a heated greenhouse in your garden, the chocolate produced wouldn’t taste as good as that, which is grown on the plantations.
Tropical FruitsWhile it isn’t completely unheard of to grow a banana tree and get a crop of bananas during a hot summer, it is unheard of to produce a crop of papaya, or coconuts. Both of these fruits grow on very tall trees, so it would be unpractical to grow them in the UK (your greenhouse would need to be huge).
You can, however, grow a range of tropical fruits in a greenhouse or polytunnel, and if you have a heated greenhouse you can grow and even greater range.
Greenhouse GrowingIn a heated (or non-heated) greenhouse you can grow a wide range of crops that are impossible (or difficult) to grow outside in the British climate. Sweet potatoes, yams, mangoes, watermelons and pineapples are just some of the more exotic crops you can grow. You can also grow much higher yields of common crops such as tomatoes, cucumbers, peppers and aubergines, or try your hand at growing okra, oranges and lemons.
With a large plot and a greenhouse or polytunnel there is not much you can’t grow. Seeds can be tricked into thinking it is spring and germinated in heated propagators and tropical fruits can be raised in greenhouses that mimic the conditions they grow in naturally. However, to successfully grow these crops requires a lot f time and effort, so it is often better to concentrate on the crops you can grow with minimum effort, and factor everything else into your budget.