FUNdamentals of Hydroponics Systems

  • Thread starter jigglybones
  • Start date
  • Tagged users None


The Fundamentals of a Hydroponics System
Understanding Vegetative Growth and Flowering / Bloom cycles

Plants undergo a number of changes throughout each life cycle. The two most distinctive are Vegetative Growth and Flowering / Bloom. During vegetative growth the plant will concentrate its energy on root formation and growing vertically towards it energy source (either the sun of lighting), it will also show significant increase in foliage. During the Flowering / Bloom stage the plant will undergo a short burst of intensive Vegetative growth which then initiates flower set. These flowers then move along to provide fruit, which will fill out and ripen in the late stages of bloom.

Lights - As a general rule for vegetative growth a plant will require long periods of light, this is generally considered to be 18 hours. For the flowering / bloom the lighting hours can be reduced to 12 hours.

Room Temp - The optimum day time temperature range is 26⁰C to 28⁰C (78.8-82.4 degrees). While the optimum lights off (night temperature for vegetative growth requires a drop of no more than 6⁰C to 8⁰c. During the flowering /bloom period the temperature drop should be no more than 10°C to 12°C.

Root Zone Temperature - This is dependent on the type of crop, but as a general rule 18⁰C to 22⁰C (64.4-71.6 degrees) is ideal range. For Winter crops use the lower end of the range and for tropical crops use the warmer end of the range. This also applies to the water temperature of the nutrient solution.

Ideal Humidity - As a general rule 40% to 65% is optimum. The conditions to consider in this situation is if the humidity is too high the breeding rates of pathogens will increase, as to will the probability of mold, botrytis, fruit rot and powdery mildew.

Prevention - Just like humans plants are prone to disease and pest attack. The best form of protection is prevention. Keep your system clean by continually sanitizing. The best option for this is to use beneficial micro organisms instead of chemical sanitizers, which are generally harmful to the plants.

Air movement - As part of photosynthesis and respiration plants require CO2 and Oxygen to survive. The simplest way to do this is to continually exchange the air within the room. As a minimum it is important to exchange the air in the room at least once every 15 minutes.
The Joker

The Joker

I would disagree with the use of beneficial micro organisms. Some of them are worthless and only keep the nasties down, not eliminated. At least in my system.

I've tried a few. I actually spent good money on Bob's brew to keep my res clean since it rests on my control bucket and gets hotter. Instead of spending 30 bucks on such a product, spend 1.99 on Hydrogen peroxide at a rate of 30 ml per gallon. Works as well as any of those money wasting products and turns into oxygen, no harm to the plants.

As far as RH, some people get great crops with a high rh, but more seem to have problems with low. I've had RH swings up to 80% but never had a mold problem as long as fans were moving.

The best way to keep PM and mites out is not to bring them into your room.

I bomb in between grows with a pyretheum bomb whether I see a bug or not. I spray with serenade in veg in the dark cycle whether I see PM or not.

I run bleach through my whole system at the beginning of every grow before the plants are in. Kills everything living in the pores of the plastic which beneficial micros will not. Then run water 24 hours, dump it, run again, dump it, then run nutes. Another cheap solution. You don't have to spend big $$$ on products to keep your system clean. Everyone has their own way, but some people spend hundreds more per grow on products to get a slightly better yield or a slightly different result. Maybe vegging a week longer for a bigger root system would save you the money.

Just sayin.


a question: how important is it to keep the nutrient solution at less than 72F? My room temps are at about 81 during the day and I don't think I can get it lower than that unless i get a chiller or something (which i cant afford). What happens to the plants if the res temps are higher? thanks. peace.


I'm with The Joker on this way to keep PM and mites away is prevention! Keep everything super clean and definitely use a bug bomb or some insecticidal soap in between grows...Another good tip he nails is that it doesnt take money to keep your room bug and pm free, takes elbow grease and a love for growing!
Top Bottom