About me

My name is Justin Hartfield. I write these letters for my daughters, or really for the grown-ups they are going to be. This page is for everyone else who finds them. Before you take advice from someone, you should know who they are. So here is who I am.

Weedmaps

In 2008 I started a website called Weedmaps with a few partners. It helped people find medical cannabis near them. Back then that was legal in only a few places and against the law almost everywhere else. I ran the company for its first eight years.

We didn’t spend our days trying to talk people into anything. We built the thing and let people use it. It grew far past anything we planned. I don’t run it day to day anymore, but most of what I know about building things, I learned there.

In 2012 I started Ghost Group, to put money into young cannabis companies at a time when most people with money wouldn’t touch them. The papers wrote about all of it back then. Some of those stories are at the bottom of this page.

Dr. Bob

The big ideas in these letters came from my teacher, Dr. Bob Melamede. He was a scientist who spent years on how a cell fixes itself, and on how the body keeps its balance. He taught me that a living thing is a flow, not a fixed thing. He died in April of 2023. I wrote a whole letter about him. Everyone else I learned from is on the Influences page.

Home

I live in Valencia, Spain, with my family. My girls are still young. They are the reason this site is here. I want them to have these letters when they are old enough to need them.

What I’m building now

My main work today is Weed.de, a company I started to help patients in Germany get medical cannabis. Richard Cowan runs it as CEO.

I also build Buds Rewards, a rewards program for people who shop at cannabis stores. Then Official Cannabis, a set of guides to cannabis strains, and Shroomap, a guide to mushroom products. Then HappyFruit, a site about hemp. And I work with VIBES on rolling papers.

Where to find me

I make short videos about the science under these letters. They’re on YouTube. I also post on LinkedIn and X. If one of the rules worked for you, or didn’t, tell me there. That’s rule five at work.