When to Fertilize Blueberries – When’s the Best Time?

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Popping sweet blueberries into your mouth is a summer treat. To get the juiciest berries possible, remember to fertilize your plants.

When to fertilize blueberries: While some blueberry plants are quite robust and only need to be fertilized once in the spring, others may need more help and therefore need to be fertilized three times a year, in the early spring, right after the petals have dropped, and again in July. Use a fertilizer that has a good amount of nitrogen and try to keep the soil acidic.

How do you fertilize blueberries?

Interestingly, blueberries have quite specific fertilizer needs. While you can generally get away with using an all-purpose fertilizer, blueberries need more care.

This is because they love soil that is acidic. In fact, if your blueberry bushes aren’t growing very well, the first step to take is to measure the soil to see if it is acidic enough.

With the need for more acid in its soil comes a special requirement for fertilizer. You should use a product that is high in nitrogen but it also should not contain any nitrates.

Another consideration is that blueberry plants are often lacking in magnesium or iron. Again, take a soil sample to see just what your soil contains and what it is lacking. Then, you can find the right fertilizer.

Organic matter

The first step in preparing your blueberry patch for exceptional berries is ensuring you have a good soil base. If you have compost handy, you should regularly add it to the blueberries, in addition to starting off with some as you plant it.

Another organic matter that is good for blueberries is manure, blood meal, or fish meal. If you are going the organic route, then mix about one pound in with the soil around your blueberry plant.

Inorganic matter

If you’re worried that your blueberry plant is not getting the specific nutrients it needs, then the best route is to purchase a pre-made inorganic fertilizer. You can readily find these products online or at your local gardening shop.

Inorganic fertilizer will have three numbers on its packaging and they refer to the ratio of nitrogen, phosphorous, and potassium. You can use a standard 10-10-10 fertilizer but if your soil is lacking in nitrogen, then you want to make sure the first number is higher.

Look to the packaging to see how much fertilizer to use although this is usually about one scoop per plant. Sprinkle the fertilizer around the soil of your blueberry plant.

Be careful that the fertilizer does not touch any part of the blueberry plant itself. Otherwise, it can actually burn the stem or leaves.

After the fertilizer is down, you want to give the area a thorough watering. This will allow the fertilizer to penetrate into the soil so the roots of the plant can find it. Watering also dilutes the nutrients so that the plant is not burned.

How often should I fertilize blueberries?

Unlike other plants, in which you can sort of fertilizing as the growing season unfolds, you will want to create a specific schedule to fertilize your blueberries. You should try to get three rounds in throughout the year.

The one caveat is if your blueberries have enough organic matter in the soil. Then, you only need to fertilize once, in the spring. Perform a quick soil test to see if your plant is lacking specific nutrients.

Phase 1

During the spring, after the last frost date in your region, you should do your first round of fertilizing. This will get your blueberry bush ready for the upcoming growing season and give it all the nutrients you need.

While you should wait until the ground warms up a bit, so that the nutrients can penetrate into the plant’s soil, you don’t want to wait too long. Aim to complete this first round of fertilizing before the first buds break on your plant.

Phase 2

The second time you should fertilize your blueberries is after what is known as ‘petal fall.’ This happens when the petals on a fruit tree or bush fall off, making way for the fruit or berries to emerge.

Petal fall is when at least 90 percent of the petals have fallen off the bush. Depending on the type of blueberry bush you have, this is usually around May or June.

Phase 3

Finally, you should fertilize your blueberry bush one last time during the growing season. This is done in early July, just as the berries are bursting with flavor.

The last fertilization ensures there are enough nutrients in the plant to focus on the growing berries. If there aren’t enough nutrients, you will still get berries but they may be very small in size.

Signs of over-fertilizing blueberries

Sign 1 – Yellow leaf edges

Unfortunately, even though fertilizer is important for the plant, if it comes into contact with the leaves or branches of a blueberry shrub, it can actually burn it. You may see yellow edges, in which case too much fertilizer has started to kill the plant.

Sign 2 – Crust on the soil

Watering after you fertilize is an incredibly important step. If you put too much fertilizer down and it doesn’t get into the soil, it will merely sit atop the soil. This is then a waste of time and money.

Sign 3 – wilted leaves

Again, the problem with over-fertilizing your blueberries is that it can actually cause the plant to die. If you see the stems and leaves start to wilt, then water a lot to try to wash away some of the fertilizer in the soil.

When is it too late to fertilize blueberries?

To get the most benefits from fertilizer, your last round should be in July, just as the berries start to become ready. Even though blueberries are a perennial plant, they do not need to be fertilized in the fall.

Instead, simply fertilize them in the early spring in order to get ready for the growing season ahead.


To get the largest, juiciest blueberries, aim to fertilize three times per year. If your plant is healthy, you can get away with it once a year and be careful not to over-fertilize.

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