I typed this up recently for folks in my area. May as well share.
Container care.
Fig trees can be productive in containers as small as 5 gallons, but will require more frequent watering and fertilizing in small containers.
They do very well in fabric container as well as self watering containers. Shielding plastic containers from the sun will reduce heat stress and watering needs.
Choose a potting mix that drains well, fig trees are not picky about potting soil otherwise, an even mix of small pine bark pieces and compost works very well.
Containers can be buried a few inches deep to allow the roots to grow out into the soil, this reduces watering and fertilizer needs and can increase growth dramatically, dig out and cut the roots outside the container in the fall (block the bottom drain holes to make digging easier).
Fertilize regularly because nutrients leach from containers quickly. High nitrogen fertilizer stimulate growth and potassium and calcium are important for fruit quality. Dry organic fertilizers work well mixed with compost and applied as a top dressing.
A vigorous and happy container tree will require frequent watering during hot and dry weather, reduce watering slightly during fruit ripening to intensify fruit flavor and sweetness.
Move the tree to a sheltered location before the first frost, especially if it grew late into the season. Store in a cool location for winter, ideally one that stays below 55 °F and above 20°F, water sparingly according to container weight. Be alert for mice, which can girdle trees.
It helps to give later ripening varieties a head start by bringing them outside to come out of dormancy a little bit early in April, but they need to be be shuffled back in if there is a chance of frost.
Growing fig trees in the ground
Choose a location that receives at least 6 hours of direct sun in summer and drains well. A spot that is sheltered near a wall is ideal to reduce winter damage.
The best time to plant a fig tree is spring and early summer, although containerized plants can be planted at any time.
Fig trees do not normally require fertilizing in local soils, which are usually silty loam. Add compost and organic mulch to improve poor soils. Apply garden lime and compost to acidic soils (below ph 6).
Fig trees can be planted deeper to protect the crown from cold, it will also encourage the tree to grow more like a bush.
Water regularly after planting to help the tree become established, use enough water to wet the root ball and surrounding soil. 2-3 times a week (more often when it is hot and dry) for about 2 months. After that the tree should not need to be watered, but would benefit during long droughts.
Protect young trees to give them the best chance during winter. One easy and effective method is to bend flexible growths to the ground and then cover with mulch, soil or other material. To make it easier, the tree can be planted at an angle. When trunks become thicker the bending should be done in stages to give the wood time to relax.
Uncover protected trees sometime in April, light frosts will not hurt them very much but a hard freeze after they have begun growing can do damage.
Prune after growth begins, make thinning cuts to allow light to penetrate the canopy and aide fruit ripening by completely removing inward facing branches, pull any excess suckers during the summer to avoid congestion.
Vigorous growth makes fig trees more vulnerable to cold damage, so avoid excess water, fertilizer and strong “heading cuts” or chops when pruning.
