Fertilizing potted fig trees is a lot different than fertilizing in-ground trees. It’s more restrictive in a way that you cannot use any fertilizer you want and still get results. The scarcity of resources in potted soil means there are strict nutrient requirements to follow.
But restrictions in fertilizer use go even further than that, especially if you need to move potted fig trees inside or completely grown indoors.
There are many questions to answer on the topic. Let’s start with the most important; the best fertilizer for container-grown fig trees.
What Is the Best Fertilizer for Potted Fig Trees?
Fig trees in containers rely on fertilizer more than in-ground ones because fewer nutrients naturally appear in the soil. That is due to less organic matter present in the soil and fewer bacteria to dissolve organic matter.
From that, we can conclude.
Water-soluble fertilizers are the best for potted fig trees due to fewer bacteria in the soil. Water-soluble fertilizers don’t need bacteria to dissolve organic matter into nutrients that a fig tree can absorb. Therefore, they are almost immediately ready for absorption.
To be more specific, I always tell people to avoid using all-purpose as their only fertilizer. It works great for in-ground fig trees, but potted fig trees need a better fertilizing strategy than that to grow amazing fig fruit.
Instead, the method which proved the best for me was to divide the growing season into three phases with three different fertilizers. Although to make a safe stop with fertilizing, I put the 1st of July as the end date of the third period. The period from the first growth to the 1st of July is divided into three equal phases.
The first phase is what I like to call the “green growth phase.” It’s a phase where young pruned fig trees need some nitrogen to regrow quickly.
However, fig trees don’t need much nitrogen after their first two years, so I like to use all-purpose fertilizer with a slight increase of nitrogen (24-8-16, for example) instead of a nitrogen-heavy one.
A good choice that always works for me is Miracle-Gro Water Soluble All Purpose Plant Food.
The second phase is the flowering phase. Fig trees don’t have separate flowers because fig fruit is an inverted flower. It acts only as a flower during its formation and first growth and later turns into fruit once it starts ripening.
All flowers require lots of phosphorus. Therefore, I use Miracle-Gro Water Soluble Bloom Booster Flower Food (10-52-10) to nudge a fig tree into fruit production and assist with fig formation.
The third phase is when figs start to ripen. All fruit needs water to swell during the ripening process. To get and keep the water, they need potassium.
Figs are known to need very little water when ripening. Too much water can even damage them by splitting their skin because they swell too fast. However, figs still need potassium.
Someway through May or June, once the figs are fully formed, I like to boost potassium with Mr. Stacky 4-18-38 Tomato Fertilizer.
You will notice that the nitrogen is only 4% because a fig tree doesn’t need nitrogen at this growth phase. However, fig trees still need phosphorus by the end of their growing season because it strengthens roots to prepare them for winter.
How Often Should I Fertilize My Potted Fig Tree?
Experienced people always say you should let a fig tree tell you what it needs. I believe that way of thinking came from areas where in-ground fig trees don’t need fertilizing at all because the soil is very rich in nutrients.
Potted fig trees are quite a different story. However, the method above can be used to know if a fig tree needs additional fertilizing after it’s been fertilized already.
My general rule is to fertilize once in each of the three phases described earlier. Then I check my potted fig trees from time to time to see if there are any signs that they need more fertilizer.
They rarely need more than what I initially give them, especially if all three types of fertilizer are used respectively.
How Much Fertilizer Does a Potted Fig Tree Need?
Now that we talked about how often a potted fig tree needs fertilizer, we should discuss quantities.
Quantities largely depend on the tree size and container/root size. Additionally, quantities depend on the specific fertilizer as well. The rule of thumb is to follow the instructions on the fertilizer package and give it at the right intervals, as I explained above.
Since fig trees don’t actually need a lot of fertilizer, I always cut the amount specified on the fertilizer package in half in the first phase. Sometimes even less than that.
In the second and third phases, which require phosphorus and potassium, I reduce the quantity even more. I would say 1/4 of what is generally used per instructions.
If fertilizer is spread correctly throughout the growing season, you will be surprised with how little fertilizer fig trees thrive and produce magnificent fruit.
When To Stop Fertilizing Potted Fig Trees?
Knowing when to stop fertilizing is equally important as knowing when to fertilize. But stopping fertilizing altogether isn’t enough. You need to know when and why to stop with each nutrient.
When people often say, “give your fig tree this and that,” they completely ignore the fact that there are other nutrients in the fertilizer as well. Some of those nutrients may be bad for the tree at that particular time.
I try to be more specific than that when telling anyone what to fertilize their fig tree with. For example, when I talk about when to give a fig tree potassium and phosphorus, I will also mention that the fertilizer rich in those two needs to have very little to no nitrogen.
N needs to be stopped early in the growing season because it can prevent fruit formation. Fig trees with too much nitrogen mid-growing season start growing wild and may prioritize growing over fruiting.
It would be best if you stopped P and K by the 1st of July for early varieties (ripe in August) and the 1st of August for late varieties (ripe in September and later).
Giving both of these to the fig tree later than that can cause problems with the fruit, such as dry fruit from too much phosphorus or prolonged fruiting season that creates the risk of frost damage when winter comes.
Why Is Stopping Fertilization Even More Important for Potted Fig Trees?
Growing fig trees in containers is a method generally practiced in colder and more humid climates.
Potted fig trees are easily protected against cold winds, frost and controlled to achieve earlier ripening. Besides, fig trees in such climates tend to stay smaller anyway, so it’s logical to grow them in containers.
To get back on point, these climates and growing conditions tend to put way more stress on the tree, making it very sensitive to fertilization timings.
A shorter growing season means it can end sooner than average each year, making it crucial to stop fertilizing on time.