Advertisements claim that without branded fertilizers your plants will dry out.
But the truth is, the best fertilizers are already in your kitchen.
For example, water from boiling potatoes is a potassium cocktail for flowering plants.

Cool it and water the petunias - the buds will cover the bush like a fur coat. And sugar water (1 tbsp. per liter) once a month is an "energy drink" for cacti and succulents.
But the most powerful stimulant is aquarium water. It contains nitrogen, phosphorus and beneficial bacteria.
Water your violets with it, and they will bloom even in winter. However, be careful with banana peels: buried in a pot, they will attract midges.
It is better to dry it, grind it into powder and add it to the soil when replanting.
And remember: if the plant does not bloom, do not feed it with nitrogen - this will only produce leaves.
Mix 1 teaspoon of dry yeast with a spoon of sugar and a liter of water, let it sit for 2 hours and water - in a week buds will appear. Nature is smarter than any chemistry!
But there are also "forbidden" fertilizers. For example, tea leaves acidify the soil and cause mold. And coffee is only suitable for azaleas and hydrangeas.
Another myth is eggshells. In their pure form, they decompose over the years. Grind them in a coffee grinder and pour vinegar over them for a day - this will make the calcium available to plants.
And don't use water from meat - it attracts rats and flies.
For the “lazy” there is a super recipe: mix nettle, dandelion and plantain in a blender (1:1:1), pour in water and leave for a week.
Strain, dilute 1:10 and water once a month. This is both fertilizer and protection against aphids. And if the flowers are affected by aphids, add a clove of garlic to the infusion - the pests will disappear in a day.