Sprouting organic cannabis plant

Organic sun grown autoflowering cannabis checklist

For those of us who grow our organic cannabis using natural sunlight you may be thinking that there is not a lot to do in the middle of winter. Au contraire I cry. If you want things to go smoothly during your summer grow then now’s the time to be planning.

I grow autoflowering cannabis because it suits me. In my book I talk through the argument as to why I choose this variety. You may also be interested to read the windowsill weed manifesto that explains the philosophy behind my grows.

As a casual grower there are some basics that you should have in order to get the most out of the summer growing season which I’ll run through below. In case you are interested in trying the same grow there’s a checklist at the bottom of the article.


I’ve got a great selection of seeds and I hope you have yours already too. If not, nows the time to grab what’s left in the seed banks. Herbies have a fantastic selection of autoflowering cannabis seeds and are discrete and trustworthy.

This season I’ll germinate more than I need and choose the strongest looking plants for the grow. I may just pop then in some mini plastic propagators I have. They are not heated but usually around beginning of May, when I intend to start, it’ll be warm enough in the greenhouse without using a heated incubator.


Unless you choose to go direct in the ground then you’ll need something to put your plant in. Up to now I’ve been growing in 10-12 litre round plastic pots. This year I’m going to give some fabric pots a try. They are a bit bigger than I normally grow in. I have a 19 litre and a 26 litre.

To get the most out of the sun I’m forced to move my pots around the garden. I’m hoping that this will be possible with these pots. The bigger the pot the more space the roots have to grow. In some miraculous balancing act by mother nature what’s up top more or less equals what’s down below. So more roots will result in greater yields. That said, under the Belgium sun my autoflowering cannabis plants will have a limited size so I’m interested to see the difference the 2 pots sizes make. Maybe 19 litres will be enough for them to max out.

Growing medium

Up until now and as described in my book I’ve been growing in a home made organic growing medium made up of one third home made compost, one third, perlite and one third coco. This year I’m gonna buy some ready mixed organic growing medium from a company called Plagron called “Batmix”. This is already loaded with natural nutrients which will see the plants through to flowering, at which point I can monitor and see if they need any additional nutrients.


I have a bottle of BioBizz Bloom kicking around so will use that in case the leaves are starting to turn yellow around flowering time. Any other issues I’ll have to pick up when the time comes.


This year I’m going to be a little more consistent in my application of neem oil and blast the young plants with it biweekly. This will strengthen their immune system and help them fight off bugs and moulds when they are big. It will also stop those pesky caterpillars and leaf miners that like to strike the plant during the vegetative period whilst the fibrous stems are not too woody. These attacks can weaken the plant and raise the risk of moulds affecting the blooming cannabis flowers. I won’t be using any other pesticides throughout the grow.


On cooler days I tend to keep the plants in a small lean to greenhouse. Whilst they are in there I have an oscillating fan to keep the air moving around the plants.

Measuring the environment

Water (pH measurement and adjustment)

I use rain water that I adjust the pH to 6.5. I’ll have a bottle of pH down on hand and make sure that my pH metre is up and running so it’s not a panic to order a new one as the growing season starts.

Temperature and humidity

I have a bunch of hygrometers that will measure the temperature and humidity in the greenhouse. This way I can open the windows if the temperature gets over 27 degrees C. I had ran a powerful extractor fan in the past but given the amount of holes in my greenhouse was probably overkill. It was also a bit noisy and made the small grow I had appear a lot more planned than I wanted it to. It lost the innocence of just popping a seed in a pot and seeing what happened. Maybe the yield will suffer slightly because of it. When it’s too hot the plants will be outside in any case.

Throughout the year I’ll go into more detail on each of the steps I’ll be taking. Hopefully to inspire others to grow their own medicine and also I’m hoping to learn more from you guys too along the way. I’m always open to tips to improve the grow.

As promised here’s the checklist. In parenthesis I give some specific brands I’ll be using but use whatever alternative that this available to you. I don’t swear allegiance to any of these.

Organic sun grown autoflowering cannabis checklist

  • Autoflowering cannabis seeds (see the seed buying guide)
  • Fabric pots (SmartPots)
  • Organic mix (Plagron Batmix)
  • Organic flowering nutrient (BioBizz Bloom)
  • Neem oil
  • Oscillating fan
  • pH meter
  • pH up/down
  • Hygrometers

If you are interested in finding out my cannabis growing journey then I invite you to check out my book Windowsill Weed: a home growers cannabis journey. It has loads of info to convince you that growing naturally at home is the best way to go for your personal cannabis supply.

Are you planning a small grow this summer? I’d love to hear how you’ll be growing yours. Please share in the comments below.

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