Pepper is a capricious crop, but with the right mineral fertilizers even a beginner will harvest like a professional.
Rule number one: no fresh manure! It causes excessive leaf growth and fruit rot.
Instead, add 10 g of calcium nitrate and 5 g of double superphosphate to the hole when planting. Calcium will strengthen the roots, and phosphorus will provide energy for growth.

Two weeks after planting, carry out the first feeding. Dissolve 20 g of ammonium nitrate, 15 g of potassium sulfate and 10 g of magnesium sulfate in 10 liters of water.
Nitrogen will support the growth of the bush, potassium and magnesium will prepare the plant for flowering. Water at the rate of 1 liter per bush.
During the period of bud formation, switch to phosphorus-potassium mixtures. Mix 25 g of potassium monophosphate and 5 g of boric acid in 10 liters of water. Spray the leaves - this will increase the number of ovaries by 2 times.
During fruiting, use potassium nitrate (30 g per 10 l of water). Potassium will make the pepper sweet and thick-walled, and the nitrogen in the composition will support the plant. Water every 10 days.
If you notice curling of leaves, this is a signal of calcium deficiency. Dilute 15 g of calcium nitrate in 10 liters of water and water under the root.
And don't forget about sulfur: 5 g of ammonium sulfate per 10 liters of water once a month will prevent yellowing of the leaves.
Watering is a separate science. Pepper loves warm water (+25°C) and regularity. Before flowering, water every 3 days with 2 liters per bush, during fruiting - every 5 days with 3 liters.
Never allow the soil to dry out: this causes the ovaries to fall off. Mulch the bed with peat or agrofibre to retain moisture.
By following these rules, you will get a pepper that will surprise you with its size and taste.