How to Grow Cannabis on a Windowsill

Do you want to try your hand at growing cannabis and harvest your own crop, even if it's small, but entirely yours? Do you lack the space indoors or a plot outdoors needed for this? Have you been eyeing that south-facing windowsill with an empty flower pot gathering dust? Have you ever wondered if cannabis can grow in the window, just like other plants do? Well, not all growers have access to suitable outdoor spaces or the resources to invest in expensive indoor cultivation equipment. In such cases, a window grow can come to your rescue. While it may not be the ideal setting, it can offer a valuable learning experience and decent yields if done right.

As you've probably guessed, this is the method of growing cannabis that we’ll be talking about.

Follow our simple recommendations – from selecting the right spot to ensuring the necessary conditions – and discover the possibilities of growing this remarkable plant. But let's start with the question that every grower, whether seasoned or totally inexperienced, has undoubtedly pondered at least once.

Can I Grow Cannabis on a Windowsill and Harvest a Bountiful Crop?

Most experts provide a straightforward answer to this complex question: anything is possible, and it's all in your hands! However, there are always nuances: you can indeed raise a cannabis seedling on a windowsill, but the yield will significantly differ from plants grown naturally outdoors or in well-equipped conditions indoors. We want to address beginners specifically. This method is perhaps the easiest way to begin cultivating cannabis and an excellent transition from theoretical knowledge about growing to practical experience. Frankly, it won't yield mind-blowing harvests, but at least, you'll gain invaluable experience. Of course, you'll get a few decent buds, but the yield won't compare to what you might see in photos of plants grown in more favorable conditions like grow tents or outdoor gardens. As we mentioned earlier, for beginners, this is an excellent starting point for understanding the plant. However, if you aim for maximum results, you'll need to decide whether sacrificing convenience and simplicity is worth the higher yield.

But it's not as bad as it may seem at first glance. Doing our research, we found reports from growers who chose a window grow and harvested around 20-30 grams of dried flowers, glistening with resinous trichomes. We'll delve into how they achieved these modest yet entirely realistic results.

Choosing the Right Location

Cannabis plants require a lot of light. If you've decided to grow cannabis on a windowsill, be sure to choose a window that receives as much direct sunlight as possible throughout the day. In simple terms, find your sunny, south-facing window. Additionally, cannabis prefers a comfortable temperature of 18-30°C and humidity levels of 40-70%. Whenever possible, try to provide these conditions either artificially by using air conditioning and humidifiers, or naturally by cultivating during the warmer months. Keep in mind that cannabis in nature grows from spring (when seeds sprout) until early autumn or winter when plants naturally wither and die.

Choosing the Right Strain

A sensible approach to strain selection is always crucial for cannabis growing, regardless of the location. However, if you've chosen a windowsill, genetics become of paramount importance. Avoid growing sativas as they require too much space for proper growth. Your ideal choice would be autoflowering, compact, resilient, genetically stable indica strains. Unlike photoperiod strains, autos aren't dependent on changes in the light cycle and will automatically switch to the flowering mode once they reach a certain age. Meeting other requirements will help you manage some of the challenges of less-than-optimal growing conditions.

Initiating Germination

Once you've settled on a strain and obtained your seeds, it's time to germinate them. We've covered this stage in detail in the blog section of our online shop.

Caring for Seedlings

Young cannabis seedlings are delicate and fragile. They thrive in a warm and humid environment. To maintain this microclimate, we recommend covering the seedling with a transparent plastic humidity dome and spraying it with water every few days. Be cautious, though – excess moisture can create an environment conducive to bacteria and fungi.

Give the seedling time to grow until it shows a few true leaves. Now you can remove the humidity dome and switch to moderate watering. No fertilizers at this stage! Just clean water, stabilized in terms of pH and PPM levels.

Use supplementary lighting! Since the seedling will naturally seek sunlight, it may stretch, which is something we want to avoid. Remember that we need a low-profile, inconspicuous bush that is easy to care for and can withstand low-stress training (LST), the form of training that’s suitable for autoflowers. At this stage, the seedling needs more light in the cold-blue spectrum, which inhibits cell division and prevents stretching. You can use a regular desk lamp with a cold-spectrum household LED light as auxiliary equipment. Just remember to remove the diffuser. Additionally, we recommend using a fan, such as PC-case cooler, whose gentle action will slightly sway the seedling, strengthening its stem.

Preparing the Pot and Soil

To grow cannabis, you'll need a pot. Remember, the larger the container, the bigger canopy you’ll get, resulting in more buds and potentially a more generous harvest. Typically, cannabis growers prefer pots ranging from 10 to 40 liters, but larger ones are unlikely to fit on a windowsill. Measure your available space and try to acommodate the largest pot possible (smart pot, air pot). One way to do this is to choose a narrow and tall pot. Also, don't forget about drainage holes and a saucer to collect runoff water. This is essential for the health of the root system.

After selecting your pot, it's time to prepare the soil, which is the ideal medium for growing on a windowsill. The better the quality of the soil, the healthier your plants will be, and the more buds they will produce. The optimal solution is to purchase a balanced soil mix from a local gardening store and blend it with approximately 30% perlite and vermiculite. This will improve drainage and oxygenate the soil, creating ideal conditions for cannabis growth. As your plant develops, you can use organic fertilizers to help it reach its full potential.

Useful tip: When young and delicate, seedlings only need water. Excess nutrients in the soil can cause nutrient burn. "Overfeeding" at this stage can have detrimental consequences. Additionally, transplanting from a starter container can cause stress, potentially affecting the seedling's growth rate and shortening its vegetative period. So, what should you do in this case? Here's a step-by-step life hack:

Prepare the pot.
Fill the bottom with drainage material (clay pebbles, gravel, crushed stone, zeolite, etc.).
Fill it halfway with prepared soil mix, leaving some for topping up later.
Place a plastic cup inside the pot.
Fill the cup with soil mix, leaving 2-3 cm from the top of the pot.
Lightly compact it.
Remove the cup.
Sprinkle the walls of the resulting hole with mycorrhiza.
Fill the hole with rinsed, slightly moist inert medium (coco coir).
Gently place the sprouted seed with the taproot facing downward into the coco medium 1-1.5 cm deep.
Lightly cover it with the same coco medium.
Place the pot on the windowsill. This approach ensures vigorous seedling growth and root development in an inert "lean" environment without access to "rich" soil nutrients. Only as the seedling grows and its roots spread beyond the coconut medium, will the plant need the nutrients present in the soil – they are essential at a more mature age.

Defoliation

Cannabis growers often resort to defoliation (the removal of excessive foliage) to stimulate plant growth and encourage the formation of more buds. When growing cannabis on a windowsill, we recommend performing only light defoliation, bearing in mind that you are caring for a small autoflowering plant that typically does not fully recover from any stress-inducing procedure before flowering begins.

Consider Supplemental Lighting

Despite the natural sunlight available on the windowsill, its source won't be consistent throughout the day. Cannabis plants require a bare minimum of 1-2 hours of light a day, but such a regimen will inevitably lead to reduced yields. Solve this issue with the help of additional lighting using household LED lamps with warm and cold spectrums, after removing their diffusers. This is a starter solution for those on a budget. Investing in professional LED lighting significantly increases your chances of a more hearty harvest.

Don't forget about safety. If your activities during the day can go unnoticed, nighttime lighting for your plants might potentially attract the attention of curious neighbors. Remove the plant from the windowsill during the night to give it supplementary lighting in a more discreet location or install simple blinds or fabric roller shades on the window.

In Conclusion

Cannabis is a relatively easy plant to grow. By creating and keeping specific conditions, you are guaranteed to obtain perfect buds. Be attentive to your plant, follow the recommendations mentioned above, choose high-quality autoflowering seeds with stable genetics, and you will surely harvest a good crop. KADAMA Seed Shop wishes you an easy and successful grow!