Superphosphate: What is it and how to use it?

The advantage of superphosphate over other fertilizers is its versatility. It is suitable for all crops and contains the necessary set of nutrients. There are several types, each differing in the content of sulfur, magnesium, and calcium. These micronutrients are vital for all plants for normal development and growth, and subsequently for producing a high-quality harvest. They help improve metabolism, increase yields, and have a positive effect on the root system and flowering.

A lack of phosphorus can negatively impact a plant. This is easily noticeable by its appearance: leaves and stems turn blue or purple, then fall off, and plant growth stops.

Fertilizer composition

Superphosphate is a mineral phosphorus fertilizer whose main component is phosphorus, or more precisely, its oxide, which is water-soluble and therefore easy to apply. The phosphorus content can vary from 20 to 50%.

Simple superphosphate consists of:

• sulfur (about 10%);
• magnesium (0.5%);
• calcium (8-12%).

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It is well suited as a fertilizer for vegetables such as:

• potato;
• turnip;
• carrot;
• radish;
• beet;
• bulbous.

It comes in two forms—granulated and powdered—and is suitable for any soil. It is used to accelerate the growth and development of plants that require sulfur.

Types of superphosphate

Gardeners can choose from several types of superphosphate fertilizer. They differ in production technology and are selected based on the application method and soil type.

• Monophosphate. It is a white powder containing 25% phosphorus oxide. It is virtually insoluble in water and has a lower effectiveness than other types. Its advantages include an affordable price and a long shelf life without changing its properties.
• Double superphosphate. It has a higher phosphorus content (approximately 45%) than other types. Other microelements (calcium sulfate, monomagnesium phosphate, and iron-aluminum phosphate) are present in smaller quantities. Its beneficial properties and application are similar to regular superphosphate.
• Granular. It has a longer-lasting effect. It consists of 50% phosphorus and 30% calcium sulfate. It differs from monophosphate in that it undergoes a special processing process, which increases the phosphorus content. It improves the soil quality.
• Ammoniated. Contains 55% potassium sulfate and 12% sulfur. It is primarily intended for crops that require sulfur, such as oilseeds. Ammoniated fertilizer is highly water-soluble and requires little skill to apply.

Preparing the fertilizer

Many gardeners don't know how much superphosphate is in 1 tablespoon and therefore may miscalculate the required amount. Granulated superphosphate contains 15-17 g per tablespoon, while powdered superphosphate contains approximately 18 g.

How to dissolve quickly

Superphosphate It's better absorbed in liquid form, penetrating the root system. However, dissolving it in water isn't as easy as it seems. To do this, take 3 liters of boiling water and dissolve 20 tablespoons of granules in it. Then, place in a warm place, stirring constantly. After 24 hours, the fertilizer will be completely dissolved. Its appearance will resemble fresh cow's milk. Additionally, you need to prepare a nutrient mixture. To do this, dilute 150 ml of the base mixture in 10 liters of water. Add 20 ml of nitrogen mixture and 500 ml of wood ash to the solution.

It's essential to water vegetables with the prepared mixture. Nitrogen is readily absorbed by plants, and phosphorus provides long-lasting nutrition. This fertilizer is an excellent option for vegetables and flowers, as well as trees and shrubs.

Correct dosage

The amount of superphosphate is calculated per square meter and depends on the crop being fertilized and the soil type. For seedlings or greens, 40 g of fertilizer is optimal, while 20 g is sufficient for root vegetables. To feed potatoes, apply 4 g per hole. Greenhouse vegetables require more nutrients, so about 80 g is needed.

Application of superphosphate

Superphosphate is an excellent fertilizer for use in your garden. It's suitable for absolutely any crop and any type of soil. However, before applying it to acidic soils, they should be deacidified with ash or lime. To do this, apply 200 g of ash or 500 g of lime per square meter. Phosphorus should not be used for at least a month after this.

Fruit trees

Phosphorus-potassium fertilizers can replace organic matter in the garden. Before applying, be sure to moisten the soil or apply them during loosening. You can water the planting and apply them afterwards; 35 g is enough for one tree, and 2 tablespoons of granules, applied to a depth of 10 cm, are needed for a berry bush.

Tomatoes and potatoes

It's best to fertilize potatoes in the spring, sprinkling 3-4 grams of granules directly into each hole. This makes it easy to calculate the dosage needed for each root crop. If you need to fertilize the entire potato planting area with superphosphate, use 20 grams of the chemical per square meter.

For tomatoes, it's recommended to apply 20 g of fertilizer per plant. It's best to apply it at root level. Since most of the phosphorus is used for proper fruit formation, it's worth applying another application during the nightshade flowering period.

Cucumbers

This crop especially requires increased phosphorus fertilization, so it will need to be fed at least four times per season. However, it's best to use superphosphate only the first two times. For the first application, dilute 60 g of superphosphate in 10 liters of water. Water the plants with this water, 400 ml per plant.

For the second time, mix:

• 10 liters of water;
• 20 g of ammonium and potassium nitrate;
• 40 g superphosphate.

Garlic

Fifteen days before planting, you can fertilize garlic with superphosphate. It is recommended to mix it with potassium fertilizer. To prepare a solution, use 20 g of superphosphate, 30 g of potassium sulfate, and 0.5 kg of ash per 10 liters of compost. Combine all ingredients and mix thoroughly.

Fertilizing tomato seedlings

If you need to use superphosphate for seedlings, it's best to choose double-granulated superphosphate, as regular superphosphate is less readily absorbed. After transplanting, you can use the tomato fertilizer solution no sooner than two weeks later. To do this, fill a 10-liter bucket with water and mix 2 tablespoons of potassium sulfate, 1.5 tablespoons of double superphosphate, and 2 tablespoons of ammonium nitrate.

Fertilize again two weeks after the first treatment. Apply the third time a week before planting the tomatoes in the ground. Add 1 tablespoon of double superphosphate and 3 tablespoons of potassium sulfate to a 10-liter bucket of water.

Strawberry

Many gardeners use organic matter and phosphorus when planting strawberries to boost the growth of young plants. The first feeding is done in the spring. For every square meter of soil, prepare a mixture of 5 kg of compost or manure, 60 g of superphosphate, and 15 g of calcium salt. The second feeding should be done in the fall with a solution of 10 liters of water, 1 kg of humus, compost, 35 g of superphosphate, and 300 g of ash.

Grape

The vine's growing medium should be enriched with a phosphorus-containing fertilizer every 2-3 years. This promotes bud development and increases sugar content. Granular fertilizer is best applied in the fall, combined with potassium supplements, which help the plant survive the winter better. Apply 55 grams of each granule per square meter to a depth of 45 cm.

Roses

These delicate flowers require mineral nutrition, but fertilizers containing beneficial elements typically contain large amounts of nitrogen, which these flowers don't need. Phosphorus is involved in bud maturation. Its effect is directed not at the formation of new branches, but at the flowers themselves. Roses should be fertilized in the fall, using a solution of 30 g of double superphosphate, 10 g of potassium sulfate, and 10 liters of water.

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Corn and sunflower

These crops need to be fertilized just before planting. Do it in the following order:

1. Superphosphate.
2. Soil layer.
3. Straw.
4. Dry leaves.
5. Seeds.

Potassium-phosphorus fertilizers increase lilies' winter hardiness, so they are best applied in the fall. To prepare the mixture, add 2 tablespoons of superphosphate and 1.5 tablespoons of potassium magnesium sulfate to a 10-liter bucket of water.

Lawn

To prevent your lawn from turning yellow suddenly, you need to carefully maintain it, mow it regularly, and add additional mineral fertilizer. In the fall, granules at a rate of 60 g per square meter are suitable for this purpose.

Indoor flowers

Fertilizing indoor plants is suitable for indoor plants regardless of the time of year. Fertilizing strengthens and nourishes roots, improving their decorative appearance. It's especially important to apply the fertilizer to flowering plants to prolong their blooming period. To prepare the mixture, you need:

• 12 g ammonium nitrate;
• 3 g potassium salt;
• 10 liters of water;
• 5 g double superphosphate.

Combine all ingredients and mix thoroughly, then water the flowers with the resulting solution.

What soils to use on?

Phosphorus can be used in any soil, but it's important to follow the recommendations to ensure it benefits plants rather than harms them. It works best in neutral and alkaline soils. It's best to deacidify acidic soils with ash or lime before planting, and then apply superphosphate a month after application.

Signs of phosphorus deficiency

Phosphorus is essential for normal plant growth. No plant can thrive without it; it helps the root system absorb micronutrients, but it's rarely found in nature. A deficiency negatively impacts the plant and can lead to the following problems:

• yellowing of leaves or acquisition of a green or blue tint;
• formation of a purple tint on the inside of the leaf;
• darkening of the core of the root vegetable.

You can get rid of such symptoms or prevent their appearance by adding phosphorus granules to the soil in a timely manner.

Methods of applying fertilizer

It's recommended to apply the bulk of the fertilizer when tilling the soil, typically in spring or fall. This can be done in several ways:

• When planting vegetables, add it directly to the holes or pits. However, it's best to purchase granulated superphosphate for this purpose;
• add to compost pit;
• water the plant with the prepared solution.

Another option is to sprinkle the fertilizer on the soil before planting and water it over it. Either way, the superphosphate will be absorbed well and produce results.

Reviews

Natalia Alexandrovna, Nizhny Novgorod

I've been using double superphosphate in my garden for many years. It's suitable for almost all crops and results in excellent harvests. It's easy to dilute and combine with other chemicals.

Alexander Danilovich, Moscow region

I've been using superphosphate in my garden for five years now. I see many advantages to using it; you don't have to spend money on large quantities of fertilizer. Superphosphate contains a whole range of essential nutrients.

Marina Vladimirovna, St. Petersburg

Superphosphate is my favorite fertilizer for my garden. I've tried granular, double, and monophosphate, and I'm happy with them all. It's easy to dilute and apply; no fuss, and the instructions are clear. It's also suitable for indoor plants, so I use it year-round.

Superphosphate has a rich composition, containing the necessary minerals for any plant in the right amounts. It's especially important to use fertilizer in areas where the same crop grows for several years. The soil becomes depleted, and insufficient nutrients reach the roots, which ultimately negatively impacts the harvest. Superphosphate is readily available. Gardeners prefer it due to its low price, good quality, and visible results.