With the right care the cultivation of fig trees can be achieved in even quite hostile environments, even when temperatures can plummet down to -200C. Being quite a hardy plant, established fig trees can be grown outdoors in a planter or directly into in the earth. However, they are best at least started off in a greenhouse, especially over their first few winters. When established a garden fig tree can add an unusual shape to the plants in your garden as well as one that can provide a delicious fruit.
If it is a single stem cut it back to about 220mm high, or if it has branches cut off the tips of any new shoots. Start a fig tree in your greenhouse in a 300mm pot, transferring it to a 600mm or larger one when required. When you transfer the plant to another pot always plant it 25mm to 50mm deeper than it was in the previous pot to encourage new growth. Also, always use clay/terracotta pot or a wooden planter, not plastic, as the natural materials are better insulators for the young plant being cooler in summer but warmer in winter.
Use a soil based compost well firmed down to about 25mm below the pot top and after an initial good watering - keep it moist, adding plenty of broken tiles or stones at the bottom of the pot or planter for drainage. Expect growth to start around March with foliage and fruit starting to appear around July. When the fruit starts to be produced give it a regular feed of a high potash fertilizer or tomato feed.
An outdoor fig tree planted in a position in the garden giving it plenty of sun will quite happily grow to 3m in height and have a spread of up to 5m. So, when planting fig trees make sure you’re giving them plenty of room to grow into and dominate. Although they like being against a wall for the reflected heat they get and protection from winds, walls can inhibit the root growth making them unstable.
So, despite being a hardy plant in extreme northerly locations protect the fig tree over winter with layers of a windbreak type of plant blanketing. This precaution should only be needed during the real depth of the winter and can usually be safely removed by March. Make sure you give the tree a good mulching in either March or April, ahead of the main growing season, other than that there’s very little you need to do in terms of further cultivation.
If you want to use figs as bushes in a border they don’t fare very well in light soils as the roots don’t bind well. You can have figs in a light soil border but you’ll need to either artificially make the earth heavier or, a better idea is to, put them in planters about 3m apart. The planter needs an annual mulching too and any pruning to maintain the bush shape should be done before the main growing season.
If you can manage to move large planters around it’s probably best to grow your fig trees in planters so that they can spend the warm months outdoors and the colder ones indoors in the greenhouse. A bonus for doing this is that an outdoor fig tree will fruit once a year whereas a greenhouse one will fruit twice.
The fruit can be picked when the fruit hangs down and the stalks are bending; you’ll also see the eye at the bottom of the fig fruit open and drip sugar. The main threat to fig trees is fig rust, a mottling of the leaves caused by getting over wet in growing seasons of heavy rain, which can be treated with a copper fungicide.