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The First Ten — free WiFi sensor for ten finished grow journals

By the Cultivar grow team · published 2026-07-26 · updated 2026-07-26 · how we source these numbers

Ten free WiFi sensors. Ten finished grow journals. That is the whole deal.

Log a grow from seed or clone through to harvest in Cultivar. Publish it. Record your dry weight. The first ten growers to do all three get a WiFi temperature and humidity sensor — free, shipped — so the next grow logs its own environment while you sleep.

0 of 10 claimed. Updated as journals qualify.

Why we are doing this, honestly

We would rather pay for ten real grows than pretend we have a thousand.

Cultivar grades your environment against stage-specific targets and gives you a coach that reads your own logs before it answers. All of that gets better the more complete, outcome-labelled grows exist in the system — grows where somebody actually recorded the light, the medium, the readings, and what came out the other end.

Ten of those is worth more to us than ten thousand signups that never log anything. So we are buying ten of them, out in the open, and telling you exactly what we get out of it.

What you have to do

Every one of these has to be true. They are deliberately specific so nobody argues later.

• The grow starts after this page went up. No backfilling from memory.
• The journal is published — it has a public page anyone can open.
• At least six weeks of logs and twelve logged events.
• At least three photos across the run.
• A harvest record with a dry weight.
• Your grow setup completed — space size, light wattage, medium, nutrients.
• One per household. Obvious nonsense is disqualified, and we will tell you why.

That grow-setup line is the one that matters most to us, and it is the one growers skip everywhere else. Without your tent size and your actual wattage, nobody can compare your harvest to anyone else's — including you. With it, we can tell you that you ran 322 watts per square metre and how that lands against every other grow at the same light level.

What the sensor does once it arrives

• Logs temperature and humidity automatically, so your environment history fills itself in.
• Feeds VPD straight into your charts, graded against the band for your current stage.
• Turns "I think it was humid that week" into a line on a graph you can point at.

It is a measuring device, not a controller. It will not turn your fans on. What it will do is end the situation where you are diagnosing a sick plant from memory.

How to start, in about four minutes

1. Create a free account — no card, no trial timer.
2. Tell the coach about your space in plain English. It asks; you answer; it fills in the fields.
3. Add your plant, pick your strain from the library, log the first watering.
4. Publish the journal when you are ready — day one is a fine time.
5. Log as you go. Two taps for a watering, a photo when something looks interesting.

What happens to your journal afterwards

Published journals show up on the strain page for whatever you grew — so the next person searching that strain finds a real grow with real numbers instead of a seed listing. That is genuinely useful to them, and it is the reason this dataset is worth building at all.

When the ten are done we will publish what they collectively say: what the spread of environments actually looked like, where the outliers were, and what we still cannot conclude from a sample this small. Ten grows is not a study and we will not dress it up as one. It is a start, and it is ten more real grows than anyone else is publishing with the light and the medium attached.

Your name is whatever you put on your account. Plenty of growers use a handle. That is fine.

Not sure yet?

Read a guide first and see whether we know what we are talking about — yellow leaves: a six-question decision tree is the one most growers need, and the VPD chart is the table our grading actually runs on. Or upload a photo to the free plant diagnosis with no account at all.

If the writing is useful, the app is built by the same people, on the same numbers.

The fine print, in plain words

We ship anywhere we reasonably can, and we pay for it. If a destination turns out to be genuinely unreachable or absurdly expensive, we will say so and offer you something else instead — we will not just go quiet. We reserve the right to disqualify entries that are obviously fabricated, and we will explain the reason rather than silently dropping you. This is not a lottery: it is first ten past the post, and the counter above is the real number.

Start your grow journal — free

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