Importance of night in hydroponics?

Question

So I've been experimenting for the last few months with hydroponics, the general goal is to have an entirely automated system. For the most part I have this in place but I'm not too happy with the results and I'm trying to eliminate potential cause for not great growth.

So I'm in Ireland, and during the summer we only really get about 6 hours of darkness at night time, and during this time, both a bit before and after, my grow light is on. Essentially my plants are getting light 24 hours a day. Now things are growing, but not as fast as they should. I have done research on nutrients and I'm monitoring on that side, but I'm wondering if perhaps the plants need a nighttime cycle? Am I over doing it by the plants essentially getting 24 hours of light everyday?

Answer 1

It depends on what kind of plants you have, but most plants are used to having a night time period. Exceptions are some plants growing in arctic regions.

I think for cultivation under lamps, mostly 16 hours light is used for growing phase, and 12 h light to get them in blooming/flowering period (at least this is what hemp home growers do).

Answer 2

I agree with CloneZero. All plants have evolved on this same planet that has specific night and day cycles...even in the arctic. Plants need darkness and a break from the work of photosynthesis. What plants are you growing? Do you know about daylight length and how that affects production of fruit/reproductive growth?

Again, what are you growing? Leafy vegetables? Ornamental foliage? Flowers and fruits? Knowing about daylight length (and strength, arctic light might as well be night) is powerful knowledge to have to grow under artificial lighting. What lamps ARE you using? How long have you been doing hydroponics? Did you ever learn gardening in the soil? What about aeration/fans/CO2...something you definitely should know with any indoor or greenhouse application.

I'd go no more than 18 hours of light per day, the rest darkness. With fans going 24/7. That will work for lettuce and ornamental foliage. To get your plants into reproductive growth for flowers and fruit you make it 12/12; 12 hours of light and 12 hours darkness. Plants should be on 18/6 at the beginning to get a nice body of vigorous photosynthetic growth going and depending on the plant, you put it into 12/12 to make it start flowering. You have to know how to do manual pollination as well. Depending on what it is you are growing.

This causes plants to start putting energy into making seed. You do have to have full control by using black plastic screens so no light even incandescent light is able to disrupt this process. You can use GREEN light to see by, however.

Plants need to 'reset' just as much as we animals do. We all evolved under the same environmental conditions with latitude, or above sea level heights and longitude constraints. No way is any plant ever going to be more productive with more light and no darkness.

Water, air, fertilizer (not 'nutrients') are critical to know and understand to be successful. Send pictures! Explain your system in detail. More about your lights...