⏳ 4 min read · Last updated: September 2026
Every product on this site carries one of two labels, and the label tells you exactly how much weight my opinion deserves. This page explains what each one means, where the pH, EC and light numbers come from, and what happens when I get something wrong.
- Hands-on tested means I have grown with it myself.
- Research pick means I have not, and the pick rests on published specifications.
- Growing numbers come from one master crop table, checked against university extension guides and published research.
- Prices come straight from Amazon and update automatically. I never type a product price by hand.
🏷️ The Two Labels
You will find the label near the top of every post that recommends products, usually right under the affiliate disclosure.
| Label | What it means | How much to trust it |
|---|---|---|
| 🌱 Hands-on tested | I have used it in my own apartment setup, on real plants, over at least one full grow. | Comments on noise, fiddliness and daily use come from my own experience. |
| 🔎 Research pick | I have not used it. The pick is based on published specifications, the manufacturer’s own figures, and the problems owners report most often. | Treat it as a well-checked shortlist, not a lived-with review. |
Most products on this site are research picks. Owning every light, pump and tower that suits a small apartment is not realistic, and I would rather say so than pretend otherwise.
🔍 How a Research Pick Gets Chosen
A product has to fit the apartment problem the post is about before anything else. With a light, that means footprint and real wattage. A pump is judged on published noise and airflow. Towers come down to floor space, because a system the size of an armchair does not fit next to a couch no matter how good it is.
After that, I check what the listing does not tell you. When a manufacturer does not publish a figure, such as a decibel rating or a tower’s full height, I write that the figure is missing rather than guessing one.
🧪 Where the Growing Numbers Come From
Every pH range, EC target, light schedule and water temperature on the site comes from one master crop table. The pH and nutrient calculator and the seed to harvest countdown use the same figures, so a post and a tool should never disagree.
I check those figures against university extension guides and published plant research. When two good sources disagree, I publish the narrower range, since a beginner is better served by a safe target than a wide one. Some figures have no solid source at all. Those are house practice, a sensible starting point rather than a researched fact.
You do not have to take my word for any of it. The crop sources page lists every number for all 39 crops next to the sources it was checked against, marks which ones are house practice, and shows what changed in September 2026.
Plants vary, though, so read every number as a starting point. Measure, watch the plant, and then adjust. If you are brand new, the complete apartment hydroponics beginner guide shows how those numbers fit together in a first setup.
📚 The Sources I Lean On Most
University sources cover fewer of the numbers than you might hope. Small indoor hydroponics is not what most extension research studies, so I would rather show you the short list than pad it:
- University of Missouri Extension, hydroponic nutrient solutions, for the general pH range
- Oklahoma State University Extension, EC and pH guide
- Cornell CEA Hydroponic Lettuce Handbook, for lettuce
- Virginia Tech Extension, for microgreens
- NASA technical report 20100039590, for disinfecting a hydroponic system with hydrogen peroxide
Past that list, most crop figures come from nutrient makers’ growing guides and experienced growers. Where a number is my own house practice, like the shared-reservoir EC of 1.5, that is what I call it.
💲 How Prices Stay Current
Where a post shows a product price, it comes straight from Amazon and updates on its own, so it is never more than a day old. Rough kit totals, like “around $75” for a starter kit, are estimates and say so. Amazon prices move often, so check the listing before you buy.
🤝 Affiliate Links
As an Amazon Associate, Urban Hydro Space earns from qualifying purchases, at no extra cost to you. The commission does not decide which product wins a roundup, and a cheap meter that does the job gets the recommendation over an expensive one that pays more. The full details are on the affiliate disclosure page.
✏️ Corrections
When a number turns out to be wrong, I change it everywhere it appears, not just in the post where someone spotted it. In September 2026 I moved spinach from 14 hours of light to 12, after controlled trials showed bolting can start at around 13 hours. Then I updated the guides and calculators that carried the old figure.
If you spot something that looks off, tell me through the contact page. I would much rather hear about it than have you lose a plant to it.
Happy growing! 🌿
Sarah, Urban Hydro Space