Don’t grow blind – A-Grade Hydroponics

October 15, 2021 steven

Tomato season has started again, this time I’ll be writing down a few revised tips from last year to help you get that heavy harvest, I found looking at the data really helped me last year so I hope it helps you too.

This is sort of a cheat sheet for the tomato plants requirements, you can comfortably follow this guide without much going wrong. Those that have the tools to measure these factors will already have an advantage and this is probably nothing new to you, but for those that don’t, here you go a list of equipment needed, so you’re not growing blind.

pH meter (Water)
EC meter (Food)
Quantum meter (Light)
Hygrometer (Temp & RH%)

Can I grow Tomato’s Indoors under lights?

Yes, and the outcomes are much healthier and more flavour-some than any outdoor grown tomato variety. Indoor growing allows the grower to take on a crop that would usually be exposed to the abiotic factors that can cause illness, foliar damage, bacterial or fungal infestations in weak or susceptible plants which affects the overall vigour of the plant and most importantly the end yield.

The numbers for light (Preferably full spectrum lighting):

PPFD: 520-700 (μmol/s.m²)

DLI: 22-30 (mol/m²/d)

Photoperiod: 12h on/12h off or 16h on/8h off, as Tomato is a day-neutral plant and does not require a longer day or night to initiate flowering. The above light recommendations are based on 12h/12h cycles. If you use a 16h/8h cycle you will need to reduce the light quantity by roughly 30% to keep within a safe range for all varieties.

(Day-neutral plants can be grown with as little as 8 hours direct light, I personally will set my lights to operate for 12-16 hours)

The numbers for nutrient solution (power of Hydrogen) & Electrical Conductivity (Fertiliser strength):

pH: 5.2-6.5

EC: 1.8-4.8

Root-Zone Temp: 18.5c-22c

Water Temp: 18.5c-26c

The numbers for environmental setting – growth phase (Lights on/Lights off):

Temp: 26.5-29.5c / 18.5c-22c

RH%: 60-70%

VPD: 1.23-1.17

How to prune my Tomato plants?

Pruning tomatoes is easy once you know what to do, throughout the growth period the plant grows quite vigorously, the central stem forms strong lateral branches that are asymmetrical, the growth nodes that emerge from tomatoes are aptly named suckers for their ability to suck energy away from the plants developing trusses. Removing suckers is crucial as the plant starts to develop flowers and form trusses on the main stem, not removing them delays harvest and maturation.