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How to Grow Weed on a Windowsill

There are a few reasons why you might want to start a windowsill grow. You might be a first-time cultivator looking to get an experience of growing and want to start small. Maybe you’re really pushed for space or working to a budget. Or you just want to grow marijuana and can’t be bothered with all the complications that go with it.

Whatever the reason, a windowsill grow is a great way for home growers to start growing cannabis without taking up too much space, using a load of equipment and sorting through a minefield of options, and keeping overheads to a minimum. This article will show you how to get started on an indoor grow with the simplest of methods.

Why Grow Weed on a Windowsill?

Growing weed on a windowsill is a cost-effective way of starting – you only really need the bare minimum in terms of equipment. This means you’ll save on timers, lights, fans, and other essentials commonly associated with indoor cultivation, such as using a grow tent. 

You not only save on buying the equipment, but also on running costs. There’s no need a grow room or hydroponics. You just need a ledge. 

For this reason and others, it’s an excellent way for beginners to get started with marijuana plants due to the reduced risk of a low outlay. Secondly, a windowsill grow requires minimal knowledge – no need to learn how to use all that equipment if you don’t need all that equipment. Thirdly, it’s an eco-friendly way of growing cannabis since you’re using natural light and not utilising any power to run your grow.

weed windowsill

There are certain drawbacks to windowsill growing, of course. You’re limited to a much smaller space, so you will produce fewer plants. You’re also working with limited hours of direct sunlight, and more depending on where your windowsill is and what time of year you’re looking to run your project. This, coupled with the lack of tech, means you won’t have a massive yield with the optimised potency. It’s good to know this out the gate.

Then there’s the privacy and security aspect – be aware that windowsill growing is not an option for everyone since your plant may be exposed. If you’re in a ground floor apartment with many passers-by and live in a region where personal cultivation is outlawed, this isn’t the project for you. Know the laws, and apply common sense.

How To Choose the Right Windowsill for Growing Cannabis Plants

Assess your options. Which windowsill is the best spot in your building for you to situate your plant? There are some factors to consider – light and privacy. Observe which one gets the most natural light. That’s the best bet for growing plants on. If you’re lucky enough to have a window that faces south, your plants will most likely enjoy between 8 and 10 hours of sunlight a day during the summer. 

Should you not have a south-facing window, an east-facing window will still give your plants enough exposure to sunlight to fuel growth. If the only option is a window facing westward, you have a different set of factors to consider – namely, greater exposure to afternoon heat. This isn’t ideal, but if it’s your only option and you’re determined to press ahead, be sure to keep your soil well hydrated.

Also, consider the privacy – will a growing cannabis plant be easily seen by neighbours or passers-by? It’s better to compromise a little bit of that sunlight exposure time by situating grow on another side of the building than to risk getting rumbled.

Should You Use Artificial Light?

If you live in a location where you don’t have a window that receives enough light – for example, if you’re surrounded by tall buildings or your only available window faces north – it’s a good idea to add some supplementary artificial grow light if your poor plant’s growth is stunted. 

LED lights are the best solution here – they’re inexpensive to run, but even better, the wavelengths emitted by LED lights mimic sunlight and help boost the growth and flowering of your cannabis plant.

Observe how much natural sunlight your plant is receiving, and when the sunlight shuts down, switch on your supplemental LEDs to make up the difference. If your plant gets 6 hours, boost with LEDs for 6. If it only gets 4 hours of natural sunlight, boost with LEDs for 8. You want to try and ensure you’re getting around 12 hours of light on your plant.

The only problem with this is, of course, privacy – you’re essentially holding a big sign up at your window saying, “Hey everyone, guess what I’m doing!”. If cannabis cultivation is illegal where you live, then this isn’t a great idea.

Make Sure You Choose the Right Pot for Your Pot

Most windowsills are pretty narrow spaces, so measure your space and choose your plant pot or pots accordingly. It is best to go with a thin pot but big enough to spread its roots. A pot with water reservoirs is highly recommended here, as standing behind glass in the summer sunlight is going to make your plant thirsty.

weed windowsill


Not only that, but consider that windowsills are often situated above radiators, and radiators (when in use) will dry your soil out faster. A good pick for a windowsill pot is a 2-litre (half-gallon) pot, as it’s small enough to fit snugly on most windowsills but spacious enough to grow a decent-sized plant. 

If your windowsill can accommodate a larger pot, go with a larger pot by all means. More pot equals more….uh…pot…

Plant Nutrition

This is where you shouldn’t skimp on cost. When growing on a windowsill, get the best soil you can find, with a high concentration of nutrients. You’re growing in smaller pots, which of course, equals less soil, so the better nutrient concentration, the better fed your plants will be, and the better fed the plant, the more optimal the growth.

Select Suitable Strains

Now that you’ve determined your lighting needs chosen your location, pots and soil – congratulations. It’s time for the best bit – the cannabis seeds! There’s one stipulation when it comes to choosing the right strain for a windowsill. After that, you’re free to choose whatever you wish. 

Make sure you go with an autoflowering variety. 

There are several reasons to use autoflowering cannabis strains for a windowsill grow project:

  • Autoflowering strains have hardy genetics, making them easy to cultivate. Since you’re relying on little to no tech to support your grow, this is essential
  • Autoflowers grow to smaller heights, and they grow quickly. From a privacy angle, this makes them the ideal choice for a sill project
  • Auto-flowering plants will reach the flowering stage without a change in light cycle/light schedule. That’s due to their genetics, they’re not photoperiod plants meaning they have a shorter life cycle. Read more on autoflowers here.

In fact, I’ll make it a little easier for you. Try one, or all, of these three strains for a windowsill grow:

Alaskan Diesel Auto

Alaskan Diesel Auto is a vigorous, fast-growing strain that is the result of crossing two auto-flowering strains, viz. Candy Fruit Auto and a Diesel Auto that was subjected to a special selection process.

Alaskan Diesel Auto is quick to mature and produces some good yields in such a short space of time. Alaskan Diesel can be grown successfully both indoors and outdoors. The average height attained is about 110 cm.

Larry Lemon OG Auto

Larry Lemon OG Auto is the auto-flowering version of this elite US Ocean Grown (OG) strain. It was created by crossing Lemon Larry (OG Kush x SVF OG) with an OG Auto, somewhat paradoxically in Orange County, California, given its name.

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With a slight Indica-dominance, Larry Lemon OG Auto produces high yields of elongated buds. Not incredibly dense but tight enough, from plants remarkably similar to the standard feminized version of Lemon Larry. It exudes a clear lemon citrus scent during flowering. 

Green Crack Auto Fem

Green Crack Auto is a great strain for all growers, including novices, as well as for the connoisseur cannabis consumer. This sativa-dominant auto hybrid is fast, productive, flavoursome and imparts an energising, upbeat effect. It’s great for all social situations.

This is quite a hungry strain. Especially during the flowering phase, so don’t stint with the nutrients if you want to obtain the best yields possible. Indoors yields will be between 500 – 650 gr/m2.

weed windowsill

THC production is around 20% with a low CBD of 0.7%. The overall effect is very uplifting accompanied by euphoric sensations and creative energy for those possessed of such talents. Its positive nature makes it ideal in a range of social situations at any time of day.

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

Duncan Mathers