When and what fertilizers to use for cucumbers in a greenhouse for a large harvest

Growing cucumbers in greenhouses and outdoors isn't much different, but there are still some nuances. Proper fertilizing is a key factor in achieving a decent harvest. Simply applying different fertilizers isn't enough; it must be done at the right time and wisely, based on recommendations and the plant's needs.

Fertilizing cucumbers in a greenhouse: a fertilizer schedule

First of all, it's important to remember that cucumbers have a short growing season. They need to be fertilized at least 3-4 times per season. The frequency of applications depends directly on the cucumber variety chosen, as well as the quality and fertility of the soil. Poor soils require more frequent fertilization, but the interval between applications should be at least two weeks.

Fertilizer schedule:

1. The seedlings are first fed before planting in their permanent location. Complex mineral fertilizers diluted with water are ideal for this purpose. They contain the optimal proportions of macro- and microelements for the growth and full development of seedlings.
2. Fertilizer is applied a second time when the young plants have adapted to the new conditions. This usually happens no sooner than two weeks after transplanting into the greenhouse. At this point, the seedlings need nitrogen most, as it promotes root development and abundant foliage growth.
3. The next feeding should be done 14 days after the previous one; during this time, plants expend a lot of energy. Solutions high in potassium and phosphorus are ideal.
4. The last time cucumbers are fertilized is during the fruiting period. To ensure beautiful and tasty fruits, potassium supplements are added. A solution of potassium sulfate or potassium nitrate works well.

If necessary, you can additionally feed the cucumbers using foliar feeding.

How to fertilize cucumbers after planting in a greenhouse

Fertilizers are applied 14 days after planting. Suitable fertilizers include mineral and organic substances high in nitrogen, which cucumbers need during this growth phase. Bird manure diluted with water at a ratio of 1:16 is preferred. A urea solution (below) is an excellent mineral fertilizer.

Compound:

• superphosphate 60 g;
• urea 1 tbsp;
• water 10 l;

Preparation:

Mineral components are added to the settled water and mixed thoroughly until completely dissolved.

Application:

The young seedlings are watered with a nutrient solution at the roots; it is better to do this in the evening or early in the morning.

How to feed cucumbers during flowering

The most important nutrients for the plant at this stage of development are potassium and phosphorus. Wood ash has a high concentration of these nutrients; it's chemical-free and provides the plants with all the necessary elements. You can also use simple or complex mineral fertilizers. Fertilizers with high nitrogen content should be avoided or applied in minimal quantities. Solutions based on "Ammophoska" are excellent:

Compound:

• "Ammophoska" 25 g;
• mullein 1l;
• water 10 l;
• any complex fertilizer 30 g;

Preparation:

Pour warm water into a bucket and add all ingredients one at a time. Mix the resulting solution thoroughly.

Application:

Liquid fertilizer is applied to the roots of the bushes in the evening or morning. Approximately 200 ml of solution is used per plant.

How to feed cucumbers during fruiting

During this period, it is recommended to use only natural ingredients—organic or folk remedies—to prevent chemicals from accumulating in the fruit. Chemicals can negatively impact the nutritional value of the fruit, especially if the vegetables are intended for children. Cucumbers respond well to herbal infusions.

Compound:

• grass;
• water;

Preparation:

Fill a container with any green herb, add warm water, and let steep for a week. Dilute with water 1:10 before use.

Application:

The procedure is best performed in cloudy weather. The resulting solution is poured onto the cucumbers at the roots, after moistening the soil first.

How to feed cucumbers to prevent them from turning yellow

Plant leaves turn yellow for various reasons, including nutrient deficiencies, poor care, or worsening weather conditions. Spraying young seedlings with a nutrient solution can help solve the problem.

Ingredients for cooking:

• 30 drops of iodine;
• 20 grams of crushed laundry soap;
• 1 liter of cow's milk;
• 10 liters of water;

Preparation:

Add all ingredients to warm, chlorine-free water and mix thoroughly until completely dissolved. Collected rainwater heated by the sun works well.

Application:

The resulting liquid is used to treat the bushes approximately once every fourteen days; the first spraying of young seedlings is carried out at the stage of 3-4 leaves.

Types of fertilizers for cucumbers in a greenhouse

Plants grown outdoors receive nutrients not only through fertilizer but also naturally. In greenhouses, these elements are supplied only through fertilizers. Therefore, indoor cucumbers require more frequent fertilization; a lack of or insufficient fertilizer can lead to soil depletion. Fertilization begins even before planting the seedlings, using both mineral and organic components. Alternating fertilizers yields good results. After fertilizing, be sure to ventilate the greenhouse.

Organic fertilizers for greenhouse cucumbers

Organic matter is beneficial for crop development, and it's also chemical-free, which is crucial for some gardeners. It can be used throughout the growing season. Solutions are most often used for fertilizing cucumbers.

Wood ash

Ideal for greenhouse plants, it contains many vital nutrients for growth and development. Ash is also an effective preventative against fungal diseases. The solution is very easy to prepare; it takes 24 hours to prepare.

Compound:

• 100 grams of ash;
• 10 liters of water;

Preparation:

Add the mixture to clean, preferably filtered, water at room temperature and let it steep for 24 hours. Stir the solution periodically.

Application:

Use throughout the growing season, with 10-14 days between applications. Apply the resulting fertilizer to the cucumbers at the roots, being careful not to let it get on the foliage.

Vitamin cocktail from herbs

Firstly, this type of fertilizer saves money, and secondly, it is made from natural ingredients and is very beneficial for cucumbers.

Compound:

• 1 kg of grass;
• 12 liters of water;

Preparation:

You can use any herb; quinoa, plantain, and nettle are all excellent choices. The herbs are seeded and crushed. Pour hot, but not boiled, water over the mixture and let it steep for 72 hours.

Application:

Strain before use. Consumption: 2-3 liters of solution per square meter of planting.

Mullein

It saturates plants with nitrogen and other useful substances and is mainly used as a third fertilizer.

Compound:

• manure;
• water;

Preparation

To make the solution, take one part mullein and ten parts water, mix well, and let it steep for two weeks in a warm place. During this time, the liquid should ferment, indicated by the appearance of bubbles.

Application:

Before use, dilute the resulting solution again 1:10 and apply it to the roots. It's best to moisten the soil first.

Mineral fertilizers for greenhouse cucumbers

Mineral fertilizers are applied throughout the growing season, taking into account the crop's specific needs at the time of application. You can use either individual minerals or complex fertilizers. They must be used with caution and in the correct dosage; an excess of certain micronutrients can have adverse effects on cucumbers and even lead to plant death. The following composition can be used for the first application.

Ingredients:

• double superphosphate;
• potassium sulfate;
• ammonium nitrate;

Preparation

Pour 10 liters of warm water into a 12-liter container, add 15 grams of ammonium nitrate, 25 grams of superphosphate, and 20 grams of potassium sulfate. Stir the solution until all components are completely dissolved.

Application:

Use the solution for watering. The resulting amount of fertilizer is enough for approximately twenty bushes.

If you notice weakening of your plants during flowering, you can remedy the situation by spraying the above-ground parts of the plants with a superphosphate solution. It's fairly easy to prepare, but it's best to do it the day before.

Compound:

• superphosphate;
• water;

Preparation:

Pour 65 grams of the mixture into a liter of hot water and let it steep for 24 hours, stirring occasionally. After the allotted time, add another 9 liters of warm water to the container with the solution.

Application:

Cucumber bushes are treated with a sprayer in the evening or morning.

Types of fertilizing cucumbers in a greenhouse

Root feeding is most often used for crops. However, in critical situations or when plants are unable to absorb nutrients for one reason or another, they are sprayed with nutrient solutions. This type of feeding is called foliar feeding. Organic and mineral fertilizers, as well as folk remedies, are used for this purpose.

Root feeding

They are used when the weather is consistently warm. Morning or evening is the preferred time for the procedure. Water the seedlings carefully, avoiding contact with the leaves. Before applying nutrients, it is recommended to pre-moisten the soil to ensure the nutrients penetrate the plant's root system more quickly.

Foliar feeding

These are used during cool summers, or if the plants' roots are poorly developed or damaged. In these situations, the plants will be unable to absorb nutrients. It's best to spray in the evening to allow the leaves to absorb the micronutrients overnight. Reduce the fertilizer concentration by half, and apply the above-ground portion of the plant using a fine-droplet sprayer. Experienced gardeners recommend using adhesives to ensure the liquid stays on the leaves for as long as possible. Foliar feeding allows plants to absorb the nutrients they need much more quickly, which is especially important during severe nutritional deficiencies. It's recommended to wear gloves and a mask before applying the fertilizer.

What should you do if your cucumbers are starting to lag behind in development?

Every gardener has experienced at least one situation where their seedlings, for no apparent reason, begin to lag in development. This is often due to a lack of nutrients. Complex mineral fertilizers can help, as they contain all the necessary micronutrients in optimal ratios.

How to understand what a plant lacks?

Seedlings often begin to lag in development, their appearance becomes unattractive, and the leaves turn yellow or dull. At first, inexperienced gardeners blame pests or disease. But finding no signs of illness, they are at a loss as to what caused the seedlings' deterioration. It turns out the cause is simple: too little or too much fertilizer.

The soil in the greenhouse will help you understand what elements your cucumbers are lacking:

• N deficiency often occurs on sod-podzolic soils;
• deficiency of B, K and Cu often occurs in light sandy and sandy loam soils;
• Mn deficiency can occur on alkaline, peaty and carbonate soils;
• in peatlands located in the lowland part of the site, a Cu deficiency often occurs;

Potassium deficiency (K)

It's especially necessary during the ripening and fruit-setting period. A deficiency significantly degrades the taste of the fruit. Their shape also changes, with cucumbers becoming narrower and gnarled near the stem. The deficiency also affects the leaves, which dry out at the edges. The situation can be corrected by generous watering. If the situation hasn't improved after 2-3 days, add an ash solution or potassium sulfate.

Nitrogen (N) deficiency

All plants require nitrogen throughout their growth period, and cucumbers are no exception. Nitrogen is especially important during the growth phase and root development. A deficiency has a significant impact on the crop. Leaves initially turn lighter, but if left untreated, they will turn yellow and fall off. Stem growth stops, and fruit does not set. The fruit's color also changes, becoming pale. If there's an excess of nitrogen, the skin of the cucumber takes on a yellowish tint and becomes covered with small spots. If nitrogen is deficient, foliar feeding with a urea solution can be done. Prepare it by mixing 15 grams of urea with 10 liters of warm water. During the fruiting period, it's best to use organic fertilizer, such as an herbal infusion.

Magnesium (Mg) deficiency

If there is insufficient amount of the substance in the soil, the plant's leaves will be unevenly colored, with light and dark spots appearing on them.

Calcium (Ca) deficiency

A sign of calcium deficiency is pale leaves with a yellowish border. Over time, they wilt and curl upward.

Boron deficiency (B)

Its deficiency manifests itself as the loss of flowers and ovaries. A light stripe can be seen on the newly formed fruits, and the cucumbers have a curved shape. A yellow border appears on the leaves.

Phosphorus (P) deficiency

Plants need phosphorus at every stage of growth. A deficiency is indicated by slow growth of shoots, smaller foliage, and discoloration of the leaves. Veins on the leaves turn purple, and in advanced stages, they darken completely and fall off. In emergency situations, plantings can be treated with a solution of ammophoska or superphosphate, prepared from one tablespoon of the substance and a bucket of settled water. This condition is quite rare and is usually associated with planting seedlings in poor soil with high acidity.

Molybdenum (Mo) deficiency

Deficiency primarily occurs in marshy areas and when crops are planted in low-lying areas with stagnant water. Plants become weak and chloritic, and fruits rot before they ripen. Soils containing heavy metals or high levels of ammoniacal nitrogen can also lead to molybdenum deficiency.

Iron (Fe) deficiency

Its deficiency manifests itself as stunted growth and flowering, as well as a lighter color at the top of the plant. The foliage along the veins has a pale green color. This problem can be remedied by applying a 5% ferrous sulfate solution to the roots.

Deficiency of copper (Cu), zinc (Zn) and manganese (Mn)

Zinc deficiency manifests itself as uneven yellowing and asymmetry of leaves. This deficiency can be replenished by adding zinc sulfate to the soil. A 0.04% solution is prepared for spraying.

A lack of manganese in the soil causes leaves to curl and turn dark green. High manganese levels can cause the plant to die.

Clear signs of copper deficiency include pale foliage, wilting flowers, and poor shoot development. Treating the soil with 1% copper sulfate in the spring can help prevent this; this is also an excellent preventative measure against fungal diseases.

Conclusion

Fertilizing cucumbers in a greenhouse has its own specific requirements, which should be taken into account when growing the crop indoors. To ensure a good harvest, it's important to follow a nutrient application schedule and know which nutrients the plant needs at any given time.