Watering length and frequency for hydroponic tomatoes

Watering length and frequency for hydroponic tomatoes

Watering length and frequency for hydroponic tomatoes

by Andrew

I’ve built a small bato bucket system in a room with 3 tomato plants. You said at least 12 irrigation cycles per day. Would that include lights out time? My tubes are putting out about 1 Gallon in 3 minutes. How long would you run them for and how much time between cycles? Thanks so much for this site, great info!

Hi Andrew,

The watering length and frequency for hydroponic tomatoes is sort of a moving target. It depends upon a number of variables, including day length, temperature, and stage of maturity of your plants. But as a rule of thumb, it’s recommended that hydroponic tomato plants receive from 1 to 2 quarts of water per day.

Another variable, though, is the type of growing medium you’re using, and the rate of drainage. Because it’s important that there’s some leachate from each watering. Otherwise, salts will build up in the pot to unacceptable levels (as indicated by high EC readings).

So you’ll need to do some experimenting to determine the optimum run time for each of your irrigation cycles. Based upon the information you’ve provided, a starting point might be a max of 30 seconds per cycle, one cycle per hour, with adjustments made as needed. Mature tomato plants will need a longer run time per cycle than immature or seedling-stage plants.

A bit of a vague answer, I know, but so much depends upon on-site conditions and on-site observations. But hopefully this will give you a good starting point.

To answer your other question: no, I never irrigate after dark. All irrigation cycles occur between dawn and dusk.

Hope this helps some. Good luck with your tomatoes, and let us know how it goes!

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Apr 11, 2015
Recirculating System
by: Andrew

Thank you for the advice!

I just planted yesterday and have been watering 30 minutes 3 times a day. I should have mentioned it’s a recirculating system, would that change the length of time? My pump timer only has 8 intervals I can set so I’ve changed it to do every 2 hours (16 hours of lights on) for 1 minute which is the smallest increment I can set. I’m growing in 3 gallon buckets with perlite.

Thank you for your willingness to share your knowledge and experience.


What you’ve set it to should be plenty. In fact, when plants are young they don’t need nearly as much water, so you can probably reduce the daily cycles for now. I might go with 4 1-minute runs for now, gradually adding cycles as the plants grow.

You do need to be sure that the root ball doesn’t try out; the plants are vulnerable to that until the roots have grown out some.

(When you plant, be sure that the original root ball is completely covered with the perlite. If any of the root ball is exposed to air, it can dry out quickly. You probably already know that, but others will be reading this. 🙂

I don’t see any reason that recirculating would effect your timing or length of runs. (I’m assuming that you’re modifying your nutrient to maintain proper EC levels.)

Good luck!

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