Any hydroponic plant nutrient solution must contain all necessary nutrients. Therefore, fertilizers for hydroponic crops in their composition contain not only salts of nitrogen, phosphorus and potassium, but also iron, boron, manganese, zinc, copper, etc. Indoor plants have several phases of the development cycle. In spring - the period of vegetation, leaf growth, in flowering plants then there is a phase of budding, and then flowering, in autumn with a reduction in daylight hours and a decrease in temperatures, there is a more or less pronounced period of rest. At all stages of plant development, a different amount of certain macro- and microelements is needed. So, during the growing season, plants need more nitrogen. Potassium and phosphorus are especially needed to plant flower buds and produce fruit. In addition, potassium increases the winter hardiness of plants .
There are special complex fertilizers for hydroponic plants, they usually contain averaged proportions of NPK. In principle, these fertilizers are designed for year-round application to water for hydroponics and for watering plants on neutral substrates (perlite, coconut fiber).
These fertilizers are ideal for deciduous plants, but not quite suitable for flowering and fruiting plants, so it is better to purchase sets of liquid fertilizers for different periods of plant development.
Etisso Hydro Vital, hydroponics fertilizer

Liquid nitrogen-phosphorus-potassium fertilizer with trace elements, specially designed for growing flower-decorative plants on hydroponics, manufactured in Germany.
Contains nutrient components in easily digestible form and optimal ratio for plant growth and development. Contains buffer components to adjust the pH of the solution.
Composition:
Nitrogen - 5.2%
Phosphorus - 5.0%
Potassium - 4.2%
Trace elements - boron, copper, iron, manganese, molybdenum, zinc, etc.
Vitamins - V1
Method of application: 10 ml of fertilizer per 10 liters of water with adjusted pH. Replenish the missing nutrient fluid level by preparing a new solution using Etisso Hydro.
The presence in the fertilizer of all macro- and microelements necessary for the plant does not yet guarantee the complete assimilation of these elements by the plant. Therefore, all Etisso liquid fertilizers contain vitamin B1, which contributes to the greatest absorption of all the necessary elements by plant roots. And you can be sure that the plant will receive all those substances that it needs so much for growth and development .
For decorative and flowering plants, additional fertilizers are needed, the kit may contain:
Liquid fertilizer for the growth period Etisso (Hydro),
Etisso Growth Liquid Fertilizer,
Composition: 7.1% total nitrogen, 3.1% R2O5 - water-soluble phosphates, 4.2% K2O5 - water-soluble potassium oxide, 0.02% Cu - copper + trace elements and vitamin V1. This fertilizer is suitable in the phase of intensive plant growth.
Etisso Flowering Liquid Fertilizer,
Composition: 3.8% total nitrogen, 7.6% R2O5 - water-soluble phosphates, 7.5% K2O5 - water-soluble potassium oxide, 0.02% Cu - copper + trace elements and vitamin V1.
Greenworld "Spezialdunger Hydrokultur," hydroponics fertilizer

Production Germany. Purpose: for all ornamental plants and plants in hydroponic systems. Makes the leaves lush and juicy green. Promotes strong and healthy growth. Prevents yellowing of leaf tips. Contains all necessary components.
Method of application: Potted crops - dissolve 5 ml of fertilizer (1/4 cap) in 2 l of water. With each 2nd watering, add fertilizer to the water. Hydroponics - 3 ml per 2 liters of water.
Composition:
N nitrogen - 4.5% (2.4% - nitrate, 2.1% - ammonium),
R2O5 phosphorus - 4.5%,
K2O potassium - 6%,
trace elements: В - 0.010%, Cu - 0.009%, Fe - 0.034%, Mn - 0.018%, Mo - 0.001%, Zn - 0.018%.
For decorative and flowering plants, additional fertilizers are needed, the kit may contain:
Liquid fertilizer for the growth period GreenWorld (Hydrokultur ),
GreenWorld Flowering Liquid Fertilizer,
Composition: (N) nitrogen-10% (carbomide 9.1%), phosphorus (P2O5) - 9%, potassium (K2O) 7%, trace elements - Fe 0.034%, B-0.010%, Cu-0.009%, Mn-0.018%, Mo-0.001%, Zn-0.018 %.
FloraDuo Bloom Hydroponics Fertilizer

Suitable for growing in soil and hydroponics, manufactured by France. At the stage of flowering/fruiting, it provides plants with everything they need according to their needs. Flora Duo is a mineral two-component concentrated fertilizer for fast growing plants with a clear difference in growth and flowering needs. Contains bioactive additives and stimulants.
Recommendation: To achieve better results, use FloraDuo Bloom in conjunction with FloraDuo Grow.
Composition (minimum allowable):
N total 1%
P2O5 5 %
K2O 3,5%
SO4 5 %
MgO 3%
Fe 0,012% Chelated 6% EDDA – 11% DPTA
Zn 0,002% Chelated EDTA
B 0,008%
Mn 0,0015% Chelated EDTA
Mo 0,004%
FloraDuo Grow HW, Hydroponics Fertilizer

Production France. Suitable for growing in soil and hydroponics, in the vegetative stage provides plants with everything they need according to their needs. Flora Duo is a mineral two-component concentrated fertilizer for fast growing plants with a clear difference in growth and flowering needs. Contains bioactive additives and stimulants. For hard water. Stabilizes pH.
Recommendation: To achieve better results, use FloraDuo Bloom in conjunction with FloraDuo Grow.
Composition (minimum allowable):
N total 5%
K2O 5,20 %
CaO 1,0 %
MgO 3%
Fe 0,06% Chelated 6% EDDA – 11% DPTA
Cu 0,005% Chelated EDTA
Zn 0,005% Chelated EDTA
B 0,01%
Mn 0,02% Chelated EDTA
Mo 0,0015%
Fertilizer for indoor flowering plants POKON
Production Ukraine. Fertilizer for indoor flowering plants Pokon contains in an optimal proportion all the nutrients needed by plants during the flowering period. Due to the high concentration of nutrients, this fertilizer is economical to use. Suitable for hydroponically grown plants in the dosage recommended by the manufacturer.
Composition:
Nitrogen (N) (urea) - 8%;
phosphoric acid (P2O5), soluble in water - 10%;
potassium oxide (K2O), soluble in water - 13%;
trace elements - boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn).
Fertilizer for ornamental and deciduous plants POKON

Production Ukraine. Suitable for all non-flowering plants (ficus, dracena, diffenbachia, philodendron, schefler, hedera and others). Due to the high concentration of nutrients, this fertilizer is more economical to use. Suitable for hydroponically grown plants in the dosage recommended by the manufacturer.
Composition:
Nitrogen (N) (2.9% nitrates, 2.7% urea, 2.4% ammonia) - 8%;
phosphoric acid (P2O5), soluble in water - 3%;
potassium oxide (K2O), soluble in water - 5%;
trace elements - boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn).
Method of use: 1 times a week, 10 mL per 1 L of water, in winter reduce the dosage to 5 mL.