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Hydroponics and indoor growing

Measure first.
Then grow.

Most indoor plants do not die from neglect. They die from guessing. A pH that drifts overnight. A tent that runs ten degrees warmer than you think. Root Plot gives you the numbers to aim for, and plain reviews of the meters, tents and tools that get you there.

Browse the reviews
See the target ranges

Target readout · typical hydroponic grow

pH

5.5 to 6.5

In range

PPM

500 to 1000

In range

RH

50 to 60 %

In range

Ranges change by plant and growth stage. The guides below explain when to move them.

Specs and manuals. Every review starts with the maker’s own numbers.

Verified owner reviews. We read what real buyers report after months of use.

No lab claims. We research. We do not pretend to test in a lab we do not have.

Start where your problem is

Three panels. One healthy grow.

Think of your grow room like a control board with three dials. Set up the space. Feed the roots. Check the numbers. When plants struggle, the fix almost always lives on one of these three panels.

Panel 01

Setup

Grow tents, grow boxes, lights, fans and ducting. A 2 by 2 foot tent with one small LED is enough to grow herbs all winter. Start small. Size the fan to the tent, not to your hopes.

Browse Setup guides

Panel 02

Feed

Growing media, nutrient solutions and pH control. Clay pebbles, coco coir and rockwool each drink differently. Mix nutrients into the water first, then adjust pH last. Doing it the other way round wastes the bottle.

Browse Feed guides

Panel 03

Check

pH meters, TDS meters, hygrometers, moisture meters and the care tools that follow. A ten dollar hygrometer can save a hundred dollar harvest. Calibrate your pH pen once a month and it will tell you the truth.

Browse Check guides

Bench picks

The reviews people open first

Each review is built around one question: what do you actually need this tool to do? A hygrometer for a greenhouse has a different job from one in a closet tent. We compare specs, read owner reports, and tell you which model fits which situation.

RH %

Check · Hygrometers

Best Hygrometer for Greenhouse

Greenhouses swing from damp dawn to dry noon. We look for sensors that cope with condensation and log the highs and lows while you sleep.

Read the review

H2O

Check · Moisture meters

Best Moisture Meter for Olive Tree

Olive trees hate wet feet. A long probe that reads deep in the pot stops the most common mistake with these trees: watering by habit instead of by need.

Read the review

pH

Check · Test strips

Best pH Level Test Strips for Water

Strips are cheap and never need calibrating. The catch is the colour chart. We compare which packs are readable in the narrow 5.5 to 6.5 band that hydroponics lives in.

Read the review

PPM

Check · TDS meters

Best TDS Meter for Carnivorous Plants

Venus flytraps and pitcher plants want water under about 50 PPM. Tap water can be five times that. The right meter makes a cheap safety check before every watering.

Read the review

BOX

Setup · Grow boxes

Best Grow Box for Plants

A grow box is a tent with the thinking done for you: light, fan and timer in one cabinet. Ideal if you have a spare corner and no patience for ducting.

Read the review

CUT

Check · Plant care tools

Best Electric Pruning Shears with Extension Pole

For the tall plants and high branches a ladder makes risky. We compare cutting diameter, battery life and how much the pole weighs after twenty minutes overhead.

Read the review

Root Plot is reader supported. When you buy through links on this site we may earn an affiliate commission at no extra cost to you. Our picks come from published specs and verified owner reviews, not from the commission.

Target ranges

Humidity is a schedule, not a setting

Here is the mistake almost every new grower makes. They set the tent to one humidity and leave it there. Seedlings love moist air. Flowering plants rot in it. Picture a cutting with no roots yet: it drinks through its leaves, so it needs humid air. By harvest the same plant has dense flowers that trap moisture, so dry air keeps mould away.

A hygrometer with a high and low memory shows you what the tent did overnight, which is where most problems start.

Learn to read your tent

Relative humidity by growth stage · commonly recommended ranges

Seedlings and clones

65 to 75 %

Vegetative growth

45 to 65 %

Flowering

40 to 55 %

Final two weeks

35 to 45 %

Bars show the middle of each range. Figures are the ranges most grower guides and equipment manuals agree on. Your plant type may ask for a little more or less.

5.5 to 6.5

pH for hydroponics

6.0 to 7.0

pH for soil

70 to 80 °F

Daytime tent temperature

Latest from the grow room

New guides on the panel

Fresh answers to the questions growers ask most. Each one is written to be read in one sitting and acted on the same day.

See every guide

Know your numbers

Four readings that explain most plant problems

You do not need a degree to run a healthy tent. You need to understand four numbers and own the cheap tools that read them.

pH

How acidic or alkaline your water is. Nutrients only dissolve properly inside a narrow band. Too far out and the plant starves with a full reservoir in front of it. Test it after every nutrient change.

PPM / EC

How strong your nutrient water is. PPM means parts per million and EC means electrical conductivity. Both measure the same thing with different units. Rising PPM between top ups means the plant is drinking water faster than it is eating food.

RH

Relative humidity, the amount of moisture in the air. High RH slows drinking and invites mould. Low RH makes leaves curl and stresses the plant. Check it at the canopy, not at the floor of the tent.

Soil moisture

How wet the root zone is, read with a probe. The top inch lies. It dries first while the bottom stays soaked. A probe reads where the roots live and ends the overwatering guesswork for good.

Find the right meter