Yes, you can grow cannabis on your windowsill and many growers do so routinely. You may not be able to grow quite the same heavy yielding monsters that can be grown professionally indoors (or outdoors in full sun). But with the right type of cannabis seeds (autoflower seeds are especially recommended) you can easily, and quickly, produce good quality harvests if you are prepared to tolerate a few compromises.
Growing cannabis on a windowsill
The pros and cons of growing cannabis on a windowsill
There are pros and cons to growing cannabis on a windowsill. If you live in a legal grow environment, you may not be too worried about passers-by seeing your plants. The main pros and cons for windowsill weed growing are below.
Pros
- Save money, no electricity costs.
- Windowsill growing is an easy introduction to cannabis growing for the beginner.
- Eco-friendly using natural sunlight.
- Reduced set up costs – no tent, air extraction equipment etc.
- Generally stable indoor temperatures.
Cons
- You may have strong indoor aromas to deal with during bloom. These can be difficult to deal with and may be noticeable to others that live in your house/apartment.
- Your plants may be visible to others from the windowsill.
- Smaller plant containers and limited light will restrict growth and eventual harvest size compared to traditional indoor/outdoor crop yields.
The glass in your window will filter out much of the UV light content which is naturally present in sunlight. That is one advantage for those growing outdoors in full direct sunlight. But it’s important to note that even those growing under LED or HPS light indoors also generally lack these UV wavelengths and still produce great crops.
How to successfully grow weed on windowsills
Although cannabis plants can bloom with as little as 1-2 hours of direct light per day the yields will be puny compared to plants that can spend 10-12 hours each day blooming under direct sunlight (or powerful LEDs). When growing weed on windowsills in the northern hemisphere it helps to have a south-facing window (those growing in the southern hemisphere should opt for a north facing window).
Choose the best cultivation spot
For northern-hemisphere growers, south facing window offers the maximum exposure to light. An east facing window gives the advantage of cooler early morning sun but may miss some of the brighter midday sun. A west facing window may expose your plants to some of the more punishingly-high afternoon temperatures.
Some windowsill growers are able to move their cannabis plants to different windows during the day, maximising their exposure to bright light. In all cases, the grower needs to move the plants to a cooler, shaded or more ventilated area if temperatures get damagingly high.
A strong aroma during bloom is inevitable, even from small plants if the genetics are pungent. Some windowsill weed growers open windows to allow a through-breeze to dissipate the smell. Others use (or install) install kitchen/bathroom-style extraction fans to mitigate indoor cannabis odours.
Pick the right pot fabric and size
Many windowsill cannabis growers use small containers often from 1-5 litres. The larger containers promote larger plants and heavier eventual yields. Air pots and small fabric sacks are recommended, giving higher root-zone oxygenation levels and more growth vigour.
Autoflower seeds are preferred over photoperiod seeds
Most cannabis windowsill growers opt for the simplicity and speed of autoflowering cannabis seeds. These grow from seed to harvest in around 75 days and will do so irrespective of the amount of light they receive. They start to bloom automatically (hence the name) after around 4-5 weeks. Autoflower seeds also tend to grow in squat, short structures, especially in small containers, producing a dominant stocky central bloom and a few side buds.
Photoperiod feminised cannabis seeds require a 12-hour dark-period to bloom. This may not always be easy to facilitate if you have stray light (e.g. from internal house lights/TV) near your windowsill.
Select suitable cannabis seed varieties
In general, all autoflower seed varieties are recommended to cannabis windowsill growers. You can decide on your preferred flavours and genetic heritage. Buying the higher THC autoflower seeds should maximise your chances of a more potent crop.
However, one stealth autoflower seed variety, Auto Duck, is particularly popular with windowsill weed growers. Auto Duck grows with a stabilised natural leaf deformity which produces webbed cannabis leaves. Their shape is similar to a duck’s foot print. This is a low-odour strain ideally suited to urban grow situations where stealth is key.
The webbed leaf shape renders Auto Duck unidentifiable as a traditional cannabis plant, especially during vegetative growth Auto Duck could pass as a kitchen herb or garden plant. She is highly recommended to cannabis windowsill growers of all types.
Don’t neglect your plants nutrient / water uptake
When growing in smaller containers, the responsibility is on the grower to ensure the plants don’t dry out through under-watering. Nor should their growth be stunted through overwatering/overfeeding.
Irrespective of grow experience, the complexity of nutrient management is simplified by the use of slow-release organic nutrients (BioTabs are market leaders and thoroughly recommended). One additional tool which may help growers is a soil moisture meter (hygrometer) which lets you know precisely when to water. Blumat enjoy a good reputation amongst growers.
Consider using supplemental artificial light
Some windowsill weed growers supplement use an overhead artificial light. These are available in various wattages from 20W upwards. This supplements the window light and is a popular yield-boosting option especially for those growing in a legal environment there are no real worries or concerns. But for those growing in areas where cannabis cultivation is still illegal the risks of growing a windowsill cannabis plant illuminated by a powerful overhead LED may simply be too great and attract unwanted attention.
Best cannabis seeds to grow on a windowsill
Growing autoflower seeds on a windowsill in small containers around 2-3 litres in size may only produce yields of ~10-20 grams per plant with heights ranging from 15-30cm tall in general. Not the same results that you might expect in a traditional indoor tent with powerful LED grow lights. But for many, windowsill cannabis growing allows the grower to harvest several plants throughout the year producing good quality buds with no significant costs other than a few autoflower seeds.
Auto Duck
Auto Duck has unique natural leaf camouflage. Without the traditional iconic marijuana leaf shape you can walk straight past Auto Duck without realising it is cannabis! The low-aroma characteristics work in favour of the windowsill weed growers. Expect an easy grow and a harvest in around 10-11 weeks.
Auto Blueberry
A naturally squat indica-dominant autoflower strain, she is well suited to windowsill weed growing. Auto Blueberry is one of two ultra-fast autoflower seeds (the other is Auto Blackberry Kush). Indoors some phenotypes may be ready in as little as 8-9 weeks after germination. The buds have a sweet blueberry muffin flavour and an effect which melts stress instantly.
Auto Blackberry Kush
Like Auto Blueberry, Auto Blackberry Kush is a notably fast growing strain. Some plants may be ready to harvest in little over two months. The buds are often dark with rich deep cherry colours and a sweet fruity taste. Potency is very high too, not only can you expect blue/purple hues in your buds, but you can expect a deeply relaxing effect that soothes body and soul.
Growing cannabis from seed to harvest on a windowsill
The combined perils of publicly visible plants and an inevitable indoor cannabis aroma deters many from windowsill cannabis growing. But some growers don’t mind these drawbacks and for them, a windowsill is an ideal opportunity to produce a few more-or-less free jars of buds each year. Maybe more if you can get away with a small overhead supplemental light to boost yields.
You won’t need a grow tent and, other than some soil, containers, nutrients & autoflower seeds, you won’t need to spend any serious cash. If you can cope with the cons of cannabis windowsill growing, you can look forward to some low-cost easy stash!