Fertilizing Fig Trees: A Guide to Optimal Growth

Are you ready to take your fig tree to the next level? Figs are not only delicious and versatile but they can also be grown in a variety of climates and settings. But, let's face it, sometimes they won't grow and produce bountiful fruit on their own. That's where fertilization comes in! It's a crucial aspect of fig tree care that can be a difference-maker in the growth, health, and yield of your tree. In this guide, I dive deep into the best fertilizer for fig trees, the significance of NPK & other essential nutrients, when to fertilize, and the secret to stimulating growth. Get ready to transform your fig tree into a fruit-producing powerhouse.

Key Takeaways

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What is the best fertilizer for fig trees?

The best fertilizer for fig trees will typically contain a good balance of macronutrients and micronutrients. Nitrogen (N), phosphorus (P), and potassium (K) are the three macronutrients that are commonly referred to as NPK, and they play critical roles in plant growth and development. Nitrogen is necessary for leaf growth and photosynthesis, phosphorus is important for root development and fruit production, and potassium helps regulate water uptake and overall plant health.

A good balance of NPK for fig trees is actually as simple as 10-10-10 or 20-10-20. In my yard, I like a ratio of 10-5-12. For fig trees that are planted in the ground, I would highly recommend doing a soil test. A soil test can go a long way toward figuring out exactly what ratio you might prefer. In fact, you may not even need an NPK fertilizer. Fig trees are incredibly good at finding the water and nutrients that they need. They can perform well even in the worst soils, but in the world of growing fig trees in containers, that's a different story.

Frequently I am asked:

Why do container fig trees need more fertilizer than trees planted in the ground?

Container fig trees need more fertilizer than trees planted in the ground because they have a limited root system and are less able to access nutrients from the surrounding soil. Additionally, the soil in a container can become depleted of nutrients more quickly than soil in a garden or field. As a result, container fig trees need to be fertilized more frequently and at higher rates to ensure that they have access to the nutrients that they need to grow and thrive.

Do "Bloom" fertilizers work?

Keep in mind that I don't think it's important to get bogged down on ratios, but whatever NPK ratio you decide to go with, make sure phosphorus is not by far the highest number. The typical "bloom" fertilizers that are marketed today are adding high quantities of what turns out to be wasted nutrients. Most soils have plenty of phosphorus and plants typically need less of it than other important nutrients.

Depending on your preferences, I've attached a large number of reputable fertilizers below. These have the right ratios and most of the necessary micronutrients. For example, you may prefer something organic or you may not want to deal with water-soluble fertilizers. A one-time application of Osmocote or Classicote once at the beginning of the growing season can provide all of the fertilizer needs for the growing season.

Other important nutrients for fig trees besides NPK

Besides the macronutrients of NPK, fig trees also require a variety of micronutrients to grow and thrive. These include calcium, magnesium, sulfur, zinc, copper, iron, and many other trace minerals. While these nutrients are needed in smaller quantities than NPK, they are still essential for plant health and should be included to some degree in the average well-balanced fertilizer found at big box stores or major online retailers.

Some of my favorite micronutrients that you want to add separately and in higher quantities to your soil are magnesium, calcium, sulfur, silica, and trace minerals from a source like rock dust or greensand.

Magnesium and calcium are found in lime and fig trees love to grow in limestone-rich soils. If you examine the nutritional content of figs and the mineral content of fig leaves, a large portion of the minerals are from magnesium and calcium in the soil. It only makes sense to make sure your soil has an adequate amount of each. Just don't get too carried away with lime as you'll raise the ph of the soil too much. You don't want to go higher than 7.5 on the ph scale.

Sulfur is another that is needed in higher quantities and a soil additive called gypsum is a great source. Sulfur is an important nutrient for fig trees, it helps in the synthesis of certain amino acids, vitamins, and enzymes that are required for growth, it improves overall health and vigor, and is necessary for the production of chlorophyll. It also can increase the tree's resistance to disease and stress, improve the color and quality of fruits, and increase the yield.

If you want healthy leaves and a beautiful tree like the one below, cover all of your soil nutrients.

Silica has several benefits for fig trees:

• Improving plant structure: Silica helps to strengthen the cell walls of plants, making them more resistant to disease, stress, and pests. It also improves the overall structure and strength of the tree, promoting healthy growth.

• Improving fruit quality: Silica can also improve the color, size, and taste of the fruit.

• Enhancing resistance to pests and diseases: Silica has been shown to increase the plant's resistance to pests and diseases.

• Improving water and nutrient uptake: Silica helps to improve the water and nutrient uptake of the tree, leading to better growth and fruit production.

Trace minerals can be supplied to fig trees through the use of organic fertilizers, compost, or mineral-rich amendments like rock dust or greensand.

Trace minerals are beneficial for fig trees in several ways:

• Improving overall tree health and vigor: Trace minerals are important for the growth and development of the tree, and a deficiency in these minerals can lead to stunted growth, reduced fruit production, and increased susceptibility to disease and stress.

• Improving fruit quality: Trace minerals play an important role in the color, size, and taste of the fruit, for example, zinc is important for the production of sugars in fruits, and iron is important for the color of the fruit.

• Improving soil fertility: Trace minerals can help to improve the soil structure and fertility, making it more beneficial for the tree's growth. They also help to promote microbial activity in the soil, which can further improve soil fertility.

• Improving resistance to pests and diseases: Some trace minerals like copper and manganese have been shown to enhance the plant's resistance to pests and diseases.

Foliar fertilizer sprays - Which is the best, when to apply them & are they effective?

Foliar fertilizer spray is a method of applying fertilizer directly to the leaves of a fig tree. This method is particularly useful for fig trees that need a quick correction of nutrient deficiencies or for trees that are grown in soil with poor nutrient availability. The fertilizer is mixed with water and applied to the leaves using a sprayer. The leaves absorb nutrients through their stomata, which are small openings on the leaf surface that allow the tree to take in carbon dioxide for photosynthesis.

It is best to apply the spray during the early morning or late evening when the temperature is cooler and the sun is not shining directly on the leaves to prevent leaf burn. It is also important to follow the instructions on the fertilizer package for the correct mixing ratios and application rates.

I really like the Dyna-Gro product line of foliar sprays. Especially the Dyna-Gro Protekt that can help tremendously with severe cases of fig rust. I also recommend trying to make your own compost tea. More on compost tea below:

Optimizing fertilizer for fig trees

According to Dr. Bruce Bugbee, by using an electrical conductivity meter, you can accurately determine if your plant needs more or less fertilizer. Simply measure and add a water and fertilizer solution to your fig tree with an mS/m of 1.3. Water the container enough for water to come through the drainage holes and catch the water in a water tray commonly used for houseplants. Measure that water with an electrical conductivity meter to see the reading of mS/m. It should be as close to 1.3 mS/m for pushing your fig tree as hard as possible.

Dr. Bruce Bugbee is a world-renowned professor and researcher at Utah State University's Crop Physiology Lab.

You can buy an electrical conductivity meter here:

Another important factor to consider when fertilizing your fig tree is the pH of your soil. pH stands for "potential hydrogen" and it measures the acidity or alkalinity of your soil. Fig trees prefer slightly acidic soil, with a pH range of 6.0 to 6.5. If your soil is too alkaline, you can lower the pH by adding sulfur. If your soil is too acidic, you can raise the pH by adding lime. It's a good idea to have your soil tested before fertilizing your fig tree, so you can adjust the pH as needed. You can also buy a soil ph meter at an inexpensive cost. Keep in mind that pH can affect the absorption of nutrients in the soil, so it's crucial to have the right pH level for your fig tree to thrive.

When should I fertilize my fig tree?

The best time to fertilize fig trees is in the spring, just before new growth emerges or shortly after. This is the time when the tree will benefit the most from added nutrients. Aiding the tree in ways early in the spring, show exponential gains later in the season.

In the past, I have used a 4-8 week fertilizer schedule. Each week I give a dose of fertilizer to the container fig trees. You could also hook your drip irrigation up to a fertilizer injector, which will add a very low dose of fertilizer every time you water making the 1.3 mS/m target easier to achieve more consistently.

If you're growing fig trees that are planted in the ground, spring is also a great time, but if your soil test is showing deficiencies, add the specific nutrients right away.

Watch the video below for 5 Spring time tips for a successful fig season. Fertilizer recommendations included!

What's the best way to stimulate fig tree growth?

The best way to stimulate fig tree growth is to optimally provide the tree with its basic needs: nutrients, water, CO2, oxygenated soil & sunlight.

In this article, I'm focusing on the nutrient portion, but higher levels of sunlight duration and intensity go a long way! The same thing can be said for increased CO2 levels that greenhouse growers benefit from and of course soil health.

Having oxygenated soil promotes the growth of healthy microbes that aid the tree in uptaking the fertilizer that we're talking about. You can add all of the fertilizer you want, but without healthy soil full of healthy microbes, you're going to struggle. The best way to get healthier soil is to occasionally add layers of mulch. Mulch breaks down and feeds the healthy soil microbes while also helping to maintain healthy levels of water and air in the soil.

You can also create compost tea. This is a surefire way to add healthy microbes right from the compost or worm castings you've harvested or created. Compost tea is created by steeping healthy soil in water. With proper aeration and food like fish emulsion, the microbes are stripped away from the soil and multiplied in number.

I would highly recommend learning from Dr. Elaine Ighram for her work on compost tea.

For container trees, I would start out with soil that's well draining. Native soil is a nice addition for extra beneficial microbes, but don't grow in 100% native soil. Especially if it's heavy clay. Instead, add soil additives to a mostly compost or worm-casting base to give it the right porosity and oxygenation. Additives like vermiculite, perlite, rice hulls, or bark are great additions. You can also add biochar that's either purchased or made at home. It's easy to make and well worth the effort! Biochar contains huge amounts of healthy microbes that stay in the soil for a long time and provide healthy water retention properties.

These are the products that I recommend as soil additives below:

Let's assume that your tree is in good health-- you can further stimulate growth with pruning. Pruning changes the hormones within our plants. Heavy winter pruning can swing the hormonal balance in favor of growth the following growing season, while summer pruning can encourage the right balance of growth and fruiting during the growing season. Summer pruning or what a lot of experienced fig growers call "pinching" is a great way to encourage branching to form. By removing the growth tip, dominance is removed and the lower lateral buds race to achieve the dominance of the apical bud that was once above them.

Having said all of this, water is the strongest driver of growth stimulation. Think of water like the on or off switch of a fig tree. In times of drought, fig trees slow down or even stop growing completely! In humid climates, fig trees don't stop growing. They can even grow right up until frost!

The downside of too much fertilizer

While it is important to provide fig trees with the proper nutrients, it is also important not to over-fertilize. This can lead to salt buildup in the root zone causing the roots to burn reducing fruit production, and even causing plant death. Too much salinity in the soil can also kill beneficial soil life. This is why you may want to choose the organic option.

Furthermore, fig growers tend to fertilize too much late in the growing season. At a time when the fig tree is fruiting. Excess nitrogen contributes to fruit cracking and the formation of mule figs, which is beautiful at a glance but lowers fruit quality. Because of this, I like to stop all feedings to my container fig trees once the fruits have formed on my trees. I want the best fruit quality possible. They'll not only taste better, but you'll also be able to harvest more of them in times of rainy weather.

What I would like to try this growing season is continuing fertilizer at the 1.3 mS/m target to observe if excessive cracking occurs at that level.

Frequently Asked Questions

Q: Where can I buy fig tree fertilizer?

A: You can buy fig tree fertilizer at most garden centers and online retailers. Keep in mind, there is no fig-specific fertilizer and anything being sold as such is simply a marketing gimmick. The fertilizers that I recommend for fig trees can be found here.

Q: How do I apply fertilizer to my fig tree?

A: You can apply fertilizer to your fig tree by spreading it around the base of the tree and watering it well. Be sure to follow the instructions on the fertilizer package for the correct amount to use.

Q: Is fertilizer necessary for my fig tree?

A: While fig trees can grow without fertilizer and not every fig tree needs fertilizer, it is however recommended to fertilize your fig tree to add missing nutrients in their appropriate quantities to ensure optimal growth and fruit production.