When To Fertilize Olive Trees

Knowing when to fertilize olive trees is the key to a healthy, productive grove. Get the timing wrong, and you might see poor fruit set or slow growth, but with the right schedule, your trees will thrive. This guide walks you through the essential seasonal feeding plan to keep your olives happy year after year.

Olive trees are tough, but they do need the right nutrients to produce those valuable fruits. Feeding them isn’t complicated, but it does require a bit of planning around their natural growth cycle. Let’s break down exactly what to do and when to do it.

This is your core schedule. The best time to fertilize olive trees is in late winter or early spring, just before the new growth flush begins. A second, lighter application can be made in early fall to support fruit development and prepare the tree for winter.

Sticking to this timing ensures the nutrients are available when the tree needs them most. Spring feeding fuels flowering and leaf growth, while fall feeding helps the fruit mature and strengthens the tree before dormancy.

Why Seasonal Timing Matters

Olives have distinct growth stages. Feeding them out of sync is wasteful and can even harm the tree or the environment.

Applying fertilizer too late in spring can encourage soft, sappy growth that’s vulnerable to summer heat and pests. Fertilizing in high summer can stress the tree when it’s conserving water. And feeding in deep winter is pointless, as the roots are mostly inactive.

The Essential Spring Application

This is the most important feeding of the year. Aim for late winter to very early spring, when the buds are beginning to swell but before flowers fully open.

Goal: To support vigorous leaf growth, strong flowering, and initial fruit set.
What to Use: A balanced, slow-release fertilizer. A formula with nitrogen (N), phosphorus (P), and potassium (K) is ideal.
Key Tip: If your soil is deficient, this is also a good time to incorporate well-composted manure or other organic matter into the top layer of soil.

How to Apply Fertilizer in Spring

Calculate the correct amount. A general rule is 1 to 2 pounds of actual nitrogen per mature tree per year. Split this between spring and fall. Always check your specific product label.
Spread the fertilizer evenly under the tree’s canopy, starting a few inches from the trunk and going out to the drip line (where the branches end).
Gently rake or water it into the top inch of soil. This helps prevent runoff and gets it to the root zone.
Water deeply after application to help dissolve and carry the nutrients down to the roots.

The Supportive Fall Feeding

The fall application is lighter and focused on different needs. Do this in early fall, about 6-8 weeks before your first expected frost.

Goal: To support fruit maturation and help the tree store energy for the next spring’s growth.
What to Use: A fertilizer lower in nitrogen but higher in potassium and phosphorus. This promotes fruit quality and root health.
Key Tip: Avoid high-nitrogen fertilizers in fall, as they can stimulate tender new growth that will be damaged by frost.

Reading Your Tree’s Signs

Your olive tree will tell you if it’s hungry. Watch for these clues that might indicate a need to adjust your schedule.

Pale Green or Yellowing Leaves: Often a sign of nitrogen deficiency, especially in older leaves first.
Very Slow Growth: If shoots are stunted and new leaves are small, the tree may need a nutrient boost.
Poor Fruit Set or Small Fruit: Can be related to a lack of potassium or other nutrients during key development stages.

It’s a good idea to get a soil test every few years. This will tell you exactly what your soil lacks, so you don’t waste money on unneeded fertilizers.

Choosing the Right Fertilizer

You have two main paths: organic or synthetic. Both can work well if applied correctly.

Organic Options

These feed the soil ecosystem as well as the tree. They release nutrients slowly and improve soil structure.

Composted manure (well-rotted)
Blood meal (high in nitrogen)
Bone meal (high in phosphorus)
Kelp or seaweed extracts (good for micronutrients)

Synthetic (Conventional) Options

These provide nutrients in a form the tree can use immediately. They are usefull for quickly correcting a known deficiency.

Look for a balanced granular fertilizer like a 10-10-10 or one formulated for fruit trees.
Controlled-release formulas are excellent as they feed the tree gradually over months.

Remember, more is not better. Over-fertilizing can burn roots, pollute groundwater, and cause excessive leafy growth at the expense of fruit.

Special Considerations for Young vs. Mature Trees

Newly planted and established trees have different needs.

Feeding Young Olive Trees

In the first year after planting, go easy. The goal is to encourage root establishment, not top growth.

Wait until the tree has been in the ground for at least 4-6 weeks and shows signs of new growth.
Use a half-strength, balanced liquid fertilizer or a light sprinkle of slow-release granules.
Too much fertilizer can damage the delicate new roots of a young tree.

Feeding Mature, Bearing Trees

Mature trees need the full seasonal program outlined above to support a heavy crop.

Their root systems are extensive, so broadcast fertilizer widely under the canopy.
Mature trees are more tolerant but still benefit greatly from consistent, scheduled feeding.
A well-fed mature tree will be more resilient to pests, disease, and weather stress.

Watering and Fertilizing: The Vital Link

Fertilizer needs water to work. Without adequate moisture, nutrients cannot dissolve and move into the root zone.

Always water your olive tree deeply after applying dry fertilizer. During dry spells in the growing season, maintain a consistent watering schedule. A stressed, dry tree cannot take up nutrients effectively, rending your fertilization efforts useless.

Common Fertilizing Mistakes to Avoid

Fertilizing at Planting: Never put fertilizer in the planting hole. It can burn new roots.
Over-Fertilizing: This is the most common error. It leads to salt buildup, root damage, and pollution.
Ignoring Soil pH: Olives prefer slightly alkaline to neutral soil (pH 6.0-8.0). If your soil is too acidic, nutrients get locked up and the tree can’t access them, even if they’re present.
Fertilizing Sick or Stressed Trees: If a tree is suffering from drought, disease, or severe cold damage, address that problem first. Fertilizer is not a medicine.

FAQ: Your Olive Tree Feeding Questions Answered

Can I fertilize my olive tree in summer?

It’s generally not recommended. Summer heat stresses the tree, and fertilizing can add to that stress. The roots are also less active. Stick to spring and fall for major applications.

How often should olive trees be fertilized?

For most trees, twice a year is perfect: once in late winter/early spring and once in early fall. Young, non-bearing trees may only need one spring feeding.

What is the best fertilizer for olive trees in pots?

Potted olives need more frequent feeding because nutrients leach out faster. Use a balanced, slow-release fertilizer in spring and supplement with a liquid feed every 4-6 weeks during the growing season.

Is Epsom salt good for olive trees?

Epsom salt provides magnesium. Only use it if a soil test confirms a magnesium deficiency. Yellowing between leaf veins can be a sign. Otherwise, it’s not necessary.

Should I fertilize an olive tree that isn’t producing fruit?

Yes, but focus on the spring application to support overall health. Lack of fruit can be due to many factors besides nutrition, like lack of pollination, pruning issues, or a need for a chilling period.

Following this seasonal guide for when to fertilize olive trees takes the guesswork out of the process. By aligning your care with the tree’s natural rhythm, you provide exactly what it needs, exactly when it needs it. The result is a robust, beautiful tree that rewards you with a bountiful harvest for years to come.