Strawberries are easy to grow and nutritious. They have lots of vitamin C. Strawberries do require supplemental fertilizer, however. This guide will tell you all about fertilizing your strawberries.
Why Fertilize Strawberries?
While strawberry plants will grow without fertilizer, they have very small berries, and they do not produce many of them. If you want a large crop of strawberries, you need to give them supplemental nutrients by fertilizing them.
How Do I Know If My Strawberries Need Fertilizer?
You can tell if your strawberries need fertilizer if they are not producing many berries and the berries you get are small. Sometimes, the leaves will turn yellow if they lack iron. June-bearing plants will not have very many runners if they lack nitrogen.
What Nutrients Do Strawberries Need?
Strawberries need carbon, hydrogen, and oxygen, which they get from the air and water. They also need nitrogen, phosphorus, and potassium, which are the numbers on the fertilizer bags. Calcium, magnesium, and sulfur are needed in smaller amounts. Finally, boron, copper, iron, manganese, molybdenum, zinc, and chlorine are needed in trace amounts.
What Type Of Fertilizer Do Strawberries Need?
Strawberries, like all plants, need lots of nitrogen. A soil test will tell you what nutrients are in your soil and whether they are available to your plants. The soil test report will make recommendations as to how much fertilizer you need to use and what you need to add. You can get soil test instructions from your Extension agent or agricultural advisor.
Strawberries prefer slightly acidic soil (pH of 5.3-6.5). If your soil is too alkaline, you will need sulfur to adjust it. If the soil is too acidic, you will need lime to raise the pH. Soil test reports give you the soil pH for your soil sample.
What Should I Consider When Choosing Strawberry Fertilizers?
There are three factors I consider when choosing a fertilizer.
I think it is important to buy the best fertilizer you can afford. Cheap fertilizers are made with cheap ingredients. The ingredients may not be as bioavailable as more premium ingredients. In addition, you usually have to use more cheap fertilizer, so you may not come out ahead monetarily. While the most expensive fertilizer is not necessarily the best, buying premium fertilizer is a good investment in your plants.
The ratio of nitrogen, phosphorus, and potassium is the next thing I check. Some fertilizers, like 10-10-10, are balanced. Others, like 16-4-8, have different amounts of nutrients. It is difficult to tell what fertilizer you need without a soil test, but 10-10-10 is a good fertilizer to use for your strawberries if you do not have one.
Fertilizers come in liquid and granular. Some fertilizers also come in spikes. Liquids are easy to use for containers and are generally available to the plants immediately. Granular fertilizers that are water soluble are usually dissolved in water and administered as a liquid. If you are growing your strawberries hydroponically, you will need to choose a liquid or water-soluble fertilizer.
Some granular fertilizers are slow-release, which means the nitrogen in them is released gradually over time. It takes about a week to ten days for the fertilizer to start becoming available, but it may last for months between fertilizations. Many granular fertilizers now are a combination of fast-release fertilizers and slow-release fertilizers. I prefer granular fertilizer for in-ground or raised bed use. Spikes are just granular fertilizers formed into a spike, which is driven into the soil near the strawberry plants.
Top 5 Best Fertilizers For Strawberries
There are lots of fertilizers for strawberries. Here are my picks for the five best.
1. Miracle-Gro Liquid All-Purpose Plant Food Concentrate – Best For Strawberries In Pots
Miracle-Gro Liquid All Purpose Plant Food Concentrate is my pick for the best fertilizer for strawberries in pots. The NPK ratio is 12-4-8. It also has iron, manganese, and zinc in it. The 32-ounce bottle is inexpensive and lasts a long time. The iron in the product guards against iron chlorosis, which turns the strawberry leaves yellow. The manganese activates many of the plant’s enzymes. Zinc is also important in activating the plant’s enzymes. This is not an organic product. The fast-release formula works immediately but has to be used every seven to fourteen days. The cap for this bottle has lines so you can tell how much concentrate you need to mix with water. Concentrates are a little more expensive upfront but usually make a lot of fertilizer. They save packaging, and you are not paying for a bunch of water when you buy them. I think concentrates are more eco-friendly than ready-to-use liquids.
Horace Hagedorn and Otto Stern, a nurseryman, founded Miracle-Gro in 1944. The first product was a fertilizer to strengthen Stern’s plants for shipment. Stern sold out to Hagedorn in the 1980s. Miracle-Gro merged with Scotts to become Scotts Miracle-Gro in 1995. Hagedorn’s son became CEO of the new company. Orlando McLean Scott founded Scotts in 1868 in Marysville, Ohio. He bred seeds for farmers. After 1900, he began to sell seeds to homeowners. The storefront in Marysville is still a Scotts store. Scotts Miracle-Gro makes fertilizers, potting soil, hydroponic chemicals, pest control, and other gardening necessities.
To use this concentrate, shake it well. For outdoor plants, use 1/3 capful (4 teaspoons) in two gallons of water. Use the solution to water 20 square feet of the garden by soaking the soil around the plants. Use every seven to fourteen days.
For indoor plants, mix one teaspoon per gallon of water. Water the soil in the container well with the solution every fourteen days.
I prefer to use liquids with my containers. I think they burn the plants less than granular fertilizers. Miracle-Gro Liquid All Purpose Plant Food Concentrate is economical and lasts a long time. It has fast-release fertilizer that can show results in as little as twenty-four hours. I use this fertilizer in those big strawberry pots outdoors, too. It can be used on strawberries in the ground or in raised beds, but I think other products are better for that.
- Concentrate lasts a long time
- Reputable company
- Not organic
- Must use every seven to fourteen days
- Better products exist for inground and raised bed strawberries
2. Espoma Organic Berry-Tone 4-3-4 Natural & Organic Fertilizer – Best Organic Fertilizer For Strawberries
Espoma Organic Berry-Tone 4-3-4 Natural & Organic Fertilizer and Plant Food for All Berries is my pick for the best organic fertilizer for strawberries. It has an NPK ratio of 4-3-4 with added calcium, magnesium, and sulfur. In addition, it has Espoma’s patented Bio-tone formula. This formula includes Bacillus microbes to improve the ability of the plant to use the nutrients in the fertilizer and one percent humic acid. The humic acid is derived from Lenardite, which is considered the premium source of humic acid. The humic acid and sulfur acidify the soil. Sulfur is also used to make amino acids, the building blocks of proteins. The calcium helps leaf and root growth, while the magnesium is involved in photosynthesis. This product is developed specifically for use on berries, including strawberries. It is certified organic, so can be used in organic gardening. I consider this a premium fertilizer.
Espoma was founded in 1929 by Herbert G. Sanders. The headquarters were established in Millville, NJ. In 1946, a fire burned the production area, and Sanders didn’t know if he should rebuild or call it quits. He found his friends and employees clearing the debris of the production area so he could rebuild, so he did. Espoma had close ties with the Holly Society of America’s founders, Clarence Wolf and Daniel Fenton. In the late 1940s, Sanders developed a fertilizer specifically for hollies, the first commercially available acidifying fertilizer. Sanders started researching and developing a wide variety of specialty organic fertilizers. Right now, Espoma is the leading producer of organic fertilizers for the retail and lawn trade. Still owned by the Sanders family, Espoma is made in the United States and distributed in the United States and Canada.
For a new strawberry bed, mix ten pounds of fertilizer into the top four inches of soil per 100 square feet. Water the fertilizer in and plant the strawberries.
For an established strawberry patch, mix five pounds of fertilizer into the top four inches of soil per 100 square feet of bed. Water the fertilizer in after spreading it. Repeat once in 45-60 days.
I like Espoma Organic Berry-Tone 4-3-4 Natural & Organic Fertilizer and Plant Food for All Berries for several reasons. I like Espoma products and use them often. I also like that the product is specially designed for berries. I prefer to use organic products in my garden, and Espoma is well-known for good organic products. I also like that the product is made in the United States. Espoma products are a bit pricey, but I think they are worth it. Their products have premium ingredients in them, and they make my strawberries grow well.
- Organic product
- Reputable Company
- Made in the United States
- Use twice a season for established plants
- Specially designed for berries
3. Triple 10 All Purpose Liquid Fertilizer 10-10-10 – Best Liquid Fertilizer For Strawberries
Triple 10 All Purpose Liquid Fertilizer 10-10-10 with Amino Acids (5.5%) & Seaweed Extract is my pick for the best liquid fertilizer for strawberries. The NPK ratio is 10-10-10, making this a good general fertilizer for your strawberry patch. The fertilizer also includes amino acids and seaweed extract to benefit the microbes in the soil that make nutrients available to the strawberry plants. Seaweed extract also contains several trace minerals to benefit your strawberry plants. This concentrate can make up to 32 gallons of fertilizer solution. There is a measuring device built into the bottle, so you don’t have to dirty a measuring cup. You can adjust the concentration of the fertilizer, so you can use it both indoors and outside. This product is not organic.
Pendelton Turf Supply was established over 30 years ago as a local distributor to golf courses. They are still family-owned. Pendelton has expanded its offerings and now provides products to commercial customers as well as homeowners. They now sell aquatic & turf pesticides, granular & liquid fertilizers, grass seeds, turf adjuvants, golf course accessories, bird seeds, and disinfectants.
To use this product, first shake it well. Use 1-2 ounces of concentrate in one gallon of water. Use the solution to water the soil around your strawberries. Repeat every two weeks. The label suggests starting with the lower concentration of one ounce in one gallon of water and increasing it to two ounces if the plants do not respond.
I would use Triple 10 All Purpose Liquid Fertilizer 10-10-10 with Amino Acids (5.5%) & Seaweed Extract on container strawberries whether they are growing outdoors or inside. I like that you can adjust the concentration from a mild solution to a strong one, depending on the plant’s needs. I would use this in a small inground or raised bed strawberry patch, but it would get expensive to water a large patch with this liquid, especially since you need to use it every two weeks. This product does not acidify the soil, which might be a problem if your soil is alkaline or marginal for strawberries. If your soil is high in phosphorus and potassium, as mine is, I would use another product with less or no phosphorus and potassium.
- Good general fertilizer
- Contains seaweed extract and amino acids for soil health
- Measuring device in the bottle for ease of measurement
- Smells bad
- Not organic
- Must use every two weeks
4. Scotts All Purpose Flower & Vegetable Continuous Release Plant Food – Best Inorganic Fertilizer for Strawberries
Scotts All Purpose Flower & Vegetable Continuous Release Plant Food is my choice for the best inorganic fertilizer for strawberries. The NPK ratio is 10-10-10, and it has sulfur in it. The granules are polymer coated with sulfur-coated urea. The product comes in a resealable bag. The granules are slow-release fertilizer that works for two months after application. When used as directed, the product will burn your plants. This product is not organic. This fertilizer is a good general fertilizer, so you can use it all over your garden, not just on your strawberries. You don’t have to buy two fertilizers, saving you money.
Scotts is an old company. As I mentioned above, it was founded in 1868 by a Union Civil War veteran named Orlando McLean Scott. He sold clean, weed-free seed out of a storefront in Marysville, Ohio. After the turn of the century, Scotts started selling grass seed to homeowners. In 1928, Scotts started producing Turf Builder, a fertilizer specially made for lawns. In 1947, Weed and Feed was the first selective herbicide and fertilizer sold to consumers. In 1995, Scotts combined with Miracle-Gro to become Scotts Miracle-Gro. The company has bought other companies and now produces fertilizers, seeds, pest products, and a line of hydroponic equipment and nutrient formulations.
To use, scatter one cup around every 30 square feet of your strawberry patch. Work the fertilizer into the top three inches of soil. Water the area thoroughly. Repeat every two months during the growing season.
Scotts is a reputable company. Inorganic fertilizers like Scotts All Purpose Flower & Vegetable Continuous Release Plant Food feed plants directly and produce quick results. I would use this product if my strawberry patch was in trouble as it will work immediately. The product is moderately priced and is cheaper than organic products. The fertilizer can be spread right from the bag, so you don’t get it on your fingers. I like that I only have to use this product once every two months instead of once every two weeks. I would not use this product on container-grown plants because it is hard to scale down the amount needed for a flowerpot. I would use a liquid for the containers instead. Be careful not to put more fertilizer than recommended, or it will burn your strawberries. This fertilizer does not acidify the soil. This can be a problem if your soil is a little too alkaline and you need to lower the pH.
- Use every two months
- Works immediately
- Easy to spread
- Bag reseals to keep fertilizer fresh
- Not organic
- Can burn plants if too much is used
5. Down to Earth All Natural Acid Mix Fertilizer 4-3-6 – Best Overall Fertilizer For Strawberries
Down to Earth All Natural Acid Mix Fertilizer 4-3-6 is my pick for the best overall fertilizer for strawberries. This is an acidifying fertilizer with an NPK ratio of 4-3-6. Cottonseed meal is the primary ingredient. This is traditionally used for plants that like acidic conditions. Other ingredients include fish bone meal, rock phosphate, langbeinite, kelp meal, and humates. The bone meal contains phosphorus, as does the rock phosphate. Langbeinte is a crystal mineral that includes manganese, sulfur, and potassium. The kelp meal contains trace minerals. Humates acidify the soil, as does the sulfur. Most of the nitrogen is slow-release, but there is some that is released immediately. This means the strawberries green up and grow immediately and keep growing for a while on the nitrogen in this product. This is an all-natural product but is not certified organic so can’t be used in organic gardens.
Jack Bates founded Down to Earth in 1977 when he could not find organic formulations of popular garden products for his customers that wanted them. His early efforts were low-tech – he mixed his fertilizer by filling 55-gallon drums and rolling them across the parking lot. Times have changed, and Down to Earth has a complete line of natural and organic fertilizers, soil amendments, composts, and potting media that work with the microorganisms in the soil to provide what plants need to grow strong, made in a modern manufacturing plant. Down to Earth uses only premium products and their formulations work with nature to best grow your plants. All of their packages are biodegradable. They sell to homeowners, nurseries, garden centers, and commercial growers that want the best organic products for their plants. Their products are made in the United States.
For new strawberry patches, mix 2.5-5 pounds of Down to Earth All Natural Acid Mix Fertilizer 4-3-6 per 100 linear feet of row into the top three inches of the soil before planting. Water well after mixing the fertilizer in the soil.
For existing strawberry patches, mix one cup per plant into the top three inches of soil around the plant when spring growth starts. Water well to activate the fertilizer. Repeat when the strawberries start to bloom. In the fall, mix ½ cup per plant into the top three inches of soil. Water well.
I think Down to Earth All Natural Acid Mix Fertilizer 4-3-6 is an excellent premium product. It is a bit pricey, but it is worth it. If your soil is acidic, you may need to use less fertilizer to avoid making it too acidic for your strawberries.
- Premium ingredients
- Formulated for acid-loving berries
- Not certified organic
- Less flexible – can’t use on vegetables
When Do I Fertilize Strawberries?
When you fertilize your strawberries is as important as how you fertilize them.
Time of Day
Always fertilize in the morning between dawn and ten a.m. Doing so allows the strawberry plant to dry before nightfall if you accidentally get some liquid on it. Liquids should be poured on the ground around the strawberry plants but not on them. Granular fertilizers should be spread around the plants but not on them. Most granular fertilizer needs to be watered after spreading so it becomes available to the plants. Some liquid fertilizers need to be watered to activate them, but most of the time, the liquid in the fertilizer suffices.
Stages of Growth
Before planting, you should spread fertilizer on the area that will be the strawberry bed and mix it in the top six inches of soil. If you have a soil test, follow the recommendations on the results. In the absence of a soil test, spread two pounds of 10-10-10 fertilizer per 100 feet of row. After the strawberries are renovated (more on that below), spread one pound of 10-10-10 fertilizer per 100 feet of row.
Day-neutral and everbearing strawberries need more nutrition than this. Spread one pound of ammonium nitrite per 100 feet of row each month from fruit set until the first of fall.
Time of Year
When exactly you fertilize your strawberries depends on where you live and your climate. Generally, you fertilize at planting and after the strawberries are done for the year the first year. From then on, you fertilize when growth starts in the spring and when the strawberries are done for the year for June bearing strawberries. For day-neutral and everbearing strawberries, you fertilize when growth begins in the spring and then every month from when the first fruit is set to the first day of fall in your climate.
How Do I Fertilize Strawberries?
For granular fertilizers, you spread them in a band parallel to and about six inches to the side of the strawberry plants. After you spread the fertilizer, you water the strawberries and the fertilizer to activate the fertilizer.
For liquids, you pour them so that the soil around the strawberries is wet, but the fertilizer doesn’t touch the plants. Pouring fertilizer on the foliage can burn it.
Signs You Are Over-Fertilizing Your Strawberries
If you put out fertilizer and the leaves of the strawberry plants turn brown and dry within a day or two, you have put out too much fertilizer and burned your plants. Flush the area with lots of water to dilute the fertilizer and save your plants.
Too much nitrogen fertilizer results in lots of leaves and runners but few or no blooms and berries. Too much phosphorus can keep the plant from taking in zinc and iron. The leaves turn yellow. Too much potassium can keep the plant from taking in magnesium and calcium. Too much boron usually kills the strawberry plant.
Homemade Fertilizer for Strawberries
One of the best fertilizers for strawberries is a one-inch layer of compost mixed into the top three inches of topsoil before planting. Don’t use raw manure as it contains disease-causing organisms that can make you really sick.
Soak two cups of your used coffee grounds in five gallons of water overnight. Use this water to water your plants in the early spring to wake up your strawberries for the year. This contains a lot of nitrogen so only use it sparingly, so you do not burn your plants.
To add potassium and several trace minerals to your strawberry patch, soak banana peels overnight and use the water to water your strawberries. Again, moderation is key.
If your soil is low in magnesium or sulfur, add one tablespoon of Epsom salt to one gallon of water and water the strawberries with it. Do not do this more than once a year or you may cause more problems than you solve.
Caring For Your Strawberries Throughout Their Lifecycle
Growing strawberries involves more than fertilizing them. Here are some tips to grow lots of delicious berries to eat.
- There are three types of strawberries: June-bearing, everbearing, and day-neutral. June-bearing strawberries have all their berries within about three weeks in the spring. Everbearing strawberries produce three bouts of berries in the spring, summer, and fall. Day-neutral strawberries produce fruit throughout the season.
- All strawberries produce runners with daughter plants on them. June-bearing strawberries produce the most runners, with up to 120 daughter plants a year.
- Plant your strawberry patch in full sun. Ten hours or more of sun is ideal, but six will suffice.
- Strawberries need a well-drained bed that does not accumulate water when it rains.
- When planting a new bed, plant your strawberries 18-24 inches apart in rows three to four feet apart. This sounds like a lot of space, but the runners will fill in the spaces quickly.
- Plant container-grown plants at the same soil level they are at in the pot.
- Plant dormant crowns so that the roots are fully buried but the crown is above the soil.
- Strawberries need about an inch of water a week. They may need more in hot climates.
- One good soaking a week will help strawberries develop a good root system. In hot climates, you may have to water twice a week.
- Water early in the morning, before ten a.m. This lets the leaves dry before nightfall, reducing the chances of diseases.
- The first year you plant your strawberries, pinch off any flowers for the first four weeks so the strawberries can concentrate on growing roots and foliage. For June-bearing plants, pinch off all the blooms in the first season. You will get more strawberries in subsequent seasons.
- For June bearing strawberries, it is important to thin the strawberries to one plant every six to eight inches after they quit bearing. Thin the older, woody strawberries and leave the younger strawberries. Fertilize with nitrogen and water well after thinning.
- After the temperature stays below 40 degrees F in cold climates, cover the strawberries with four to six inches of straw or mulch to protect them for the winter. You do not have to do this in warm climates.
- Remove any mulch on top of the plants in the early spring.
- Leave mulch between plants and around them to keep the fruit off the soil.
- Keep weeds out of the strawberry patch. Strawberries do not compete well with weeds, and the weeds will choke out the strawberry plants.
- Strawberry plants have shallow roots, so be very careful when hoeing around them.
- Pick strawberries when they are completely red. Some berries have white shoulders where the leaves block the sun.
- Pick strawberries when they are dry and put them in the refrigerator immediately after picking.
- Pick your strawberries daily early in the morning to get the best harvest.
- Strawberries don’t keep long even in the refrigerator (3-10 days, depending on variety), so use them up quickly.
- In late summer, mow the strawberry patch and pick up all the leaves and stems that are cut. In about two weeks, the strawberries will grow new leaves. Doing this is called renovating the strawberries and reduces diseases. Thin the beds back to their original width so the plants are not crowded.
- Fertilize the plants in the early fall so they can have enough nutrients to make it through the winter and come out of dormancy in the spring.
- Avoid getting the leaves and stems wet when watering your strawberries. Use drip irrigation or a soaker hose.
- Planting 125 plants will provide a family of four with plenty of fruit to eat fresh and freeze or preserve.
- Do not plant strawberries where berries, tomatoes, potatoes, or peppers have been planted before to reduce the incidence of diseases.
- Buy only healthy-looking, certified disease-free plants.
- Plant more than one variety of strawberries to reduce the likelihood of one problem wiping all your strawberries out.
- Some strawberry varieties are tart, some are sweet. Choose the type of berry you like to plant.
- In hot climates, June-bearing plants are the most successful. Everbearing and day-neutral plants do not do well in the heat.
- As you open each bundle of strawberry plants, set them in a container with some water in it to keep them from drying out.
- The time from bloom to harvest varies from 18-45 days, depending on the variety and weather.
- Leave the caps of leaves on the strawberry until you are ready to eat it so they will store longer.
- Strawberries are vulnerable to many diseases. Plant resistant varieties so you do not have as much trouble with them. Oklahoma State has a list of some disease-resistant varieties.
- Strawberries are very vulnerable to herbicide injury. Do not use herbicides near your strawberry patch.
- Day-neutral strawberry plants will need to be replaced every three years. Other strawberry plants will produce well for about five years before needing to be replaced.
Strawberries love acidic soil and need fertilizer to bear many berries. My pick for the best fertilizer for containers is Miracle-Gro Liquid All Purpose Plant Food Concentrate. The liquid is easy to use on potted strawberries. My pick for the best liquid fertilizer for strawberries is Triple 10 All Purpose Liquid Fertilizer 10-10-10 with Amino Acids (5.5%) & Seaweed Extract. Triple 10 is a good general fertilizer, and this one has lots of extra goodies for your soil and plants. My pick for the best organic fertilizer for strawberries is Espoma Organic Berry-Tone 4-3-4 Natural & Organic Fertilizer and Plant Food for All Berries. This fertilizer is formulated just for berries, and Espoma is a reputable company with lots of experience making fertilizers. My pick for the best inorganic fertilizer for strawberries is Scotts All Purpose Flower & Vegetable Continuous Release Plant Food. This is another triple 10 fertilizer with a slow-release formula, so it won’t burn your plants if used as directed. My pick for the best overall fertilizer for strawberries is Down to Earth All Natural Acid Mix Fertilizer 4-3-6. It is formulated just for berries and is a good acidifier if your soil is not as acidic as strawberries need.