yield per square foot autoflowers

Autoflower yield, what you can expect

When growers talk about the amount of yield they get from their plants, they are referring to the amount of bud that is harvested from their plants. Yield is the weight of the harvested and dried weed flowers. This is the most effective method of assessing the efficiency of the operation. As all growers want to produce as much weed as possible from their plants, you will not be surprised to learn that growers are always trying to find ways of increasing their yield. Especially when it comes to autoflowers.

In the past, autoflowers were known and often avoided by growers because of their limiteds yields. Fortunaly, these days there are many autoflower species that are capable of producing great yields. But how much yield can you expect from an autoflower? Let’s have a closer look at the autoflower yield.

How to measure yield?

There are several ways you can do this. One of the best methods is to work out how much gram of bud is produced by each plant. This is done simply by weighing the total amount of dried bud from a single plant. However, for working out the total yield, this method is only useful if all your plants are roughly the same size.

Grams per square feet

Measuring grams per square feet is another parameter which allows growers to compare different grow rooms with the same dimension but varying growing conditions. It is calculated by dividing the total production weight by the square footage of growing space. Grams per cubic feet is another variation that is practical if you are using a vertical growing method. If growing indoors, you may wish to calculate your yield by measuring grams per watt or grams per light or kilowatt-hour. The latter is recognised as the industry standard for professional growers and is calculated by dividing the total weight of harvested dry bud by overall daily energy usage (kWh)

Differences in yield

There is no one set of guidelines to advise growers on how to do this for several reasons. Firstly, there are many strains of cannabis, many of which thrive in vastly different growing conditions. Secondly, growing environments also vary enormously – whether plants are grown indoors or outdoors means that every grow is potentially different. And that doesn’t even take into account the impact of nutrients, the length of the flowering cycle and the use of growing methods such as ScroG.

Tips for the best indoor autoflower yield

Autoflowers are varieties of cannabis that automatically produce buds without the grower having to work out the best time to put the plants into the flowering phase by altering the amount of light each plant receives. Autoflowers proliferate and have the potential to produce vast yields, but you need to know what you are doing. To help you get started and hopefully prevent you from making mistakes that result in disappointing returns, we’ve created a guide to growing autoflowers both indoors and outdoors with tips and tricks for each to give you the best chance of a bumper crop in a short space of time.

Autoflowering cannabis seeds differ from standard seeds as they only start to flower after a specified period, and this doesn’t depend on the number hours of daylight. Autoflowers seeds are therefore the ideal choice if you need a steady supply of weed.

Here are some answers to commonly asked questions about growing auto-flowering weed indoors and to maximize yield:

How much light do autoflowers need?

Growers often disagree about the amount of light autoflowers need each day, the advice can range from 16 to 24 hours per day depending on the strain. However, 18 hours of light a day and 6 hours of darkness is generally recognised as a standard, and this applies throughout the lifecycle of the plants.

What nutrients do autoflowers need to achieve the best yield?

From the first day to the thirteenth day, the plants should only be given water. After two weeks, you can add a tiny bit of growth nutrients. After four weeks, (Day 28), give the plants a few flowering nutrients for the next month. Feeding the plants should be ceased approximately seven days before harvest.

Some producers of nutrients recommend using high doses of fertilising products, but we only recommend using moderate quantities as recommended by the manufacturer. Don’t forget that an overdose could cause root burn and destroy your plant!

What soil should I use for my autoflowers?

Getting the soil right is essential no matter what variety of cannabis seed you use. Usually, auto-flower seeds prefer light soils. Traditional potting soil is not ideal for growing cannabis. We advise using professional potting soil or Californian potting soil from a “grow-shop” (hydroponics). You could also make your own soil mixture by mixing equal quantities of peat moss, compost, perlite and vermiculite (the last two need to be previously moistened with water).

What sized containers do I need?

Most auto-flowering cannabis seeds do not develop into huge plants. We recommend using pots with a volume of fewer than 15 litres.

When choosing a large pot, the plants will have space to develop more roots, and they will also grow wider and taller – not ideal for indoors unless you live in a palace.

If you meet the above conditions, growing auto-flowering cannabis plants should be a breeze.

Tip for the best outdoor autoflower yield

If you are going to grow auto-flowering seeds, you need to have a clear idea in your head. Auto-flowers have such a short life cycle – two months from cultivation – that it is essential to optimise your resources even before you get started. While feminised varieties, whose life cycle can extend up to four months, have the opportunity to recover from invasions or nutritional failures, auto-flowering plants get going at full speed, so every step counts.

But there’s no need to worry; their superior genetics make them true resistance champions. The auto-flowering varieties have genetics derived from Ruderalis, a variety native to the harsh climatic regions of the north of Europe and which has adapted to the more challenging environmental conditions by developing extraordinary rapidity and excellent resistance to bad weather in the region. However, proper planning and the best genetics from the start is essential to allow your auto-flowering plant to maximise the chance of success.

Tip: check all our top quality autoflowering seeds

How long does the auto-flowering season last?

Autoflowering plants love the hot, sunny weather and depending on the length of your summer; you may be able to enjoy several harvests. In southern Europe, you can sow the first crop between the second week of April and the beginning of May, after the frosts and when the days are longer. Harvest comes at the end of July, and it is possible to cultivate again in early August, to harvest for a second time in October.

In northern and central Europe, wet and cold weather is much more common, there is less sun, and the summer tends to be shorter, so only one crop is realistic. Sow in early June when the soil is warm to the touch to aim for a harvest at the end of August.

What pests pose a risk?

Autoflowering genetics are less likely than non-automatic varieties to suffer from insect invasions, even if they are not immune. Indeed, they have such a rapid life cycle that insects and other pests do not have the material time to become a serious issue for the plant because it does not give them time to reproduce sufficiently.

However, excess moisture should be avoided to prevent fungi.

What sort of compost should I use to increase the yield?

Autoflowering plants prefer a light, airy substrate to allow them to make the most of resources, develop their roots well and speed up all their metabolic processes. To do this, you need 10 litres of the substrate, made up of 1/3 of coconut fibre and 2/3 of peat or pre-prepared substrate.

What sized containers should I use to achieve the best yield?

If not growing directly in the ground, the smallest pot size you should use is between 7-15 litres to ensure your plants grow as large as possible. It is essential not to re-pot them repeatedly – auto-flowers find being repotted stressful. Plant the seeds directly in the container you intend to use.

How much water do auto-flowers need outside?

Autoflowering varieties cope with a lack of water better than feminised ones and don’t like being over-watered, so it is better to water them in small quantities. Never let the plant’s roots soak – but water frequently to promote oxygenation. The volumes required really depend on the weather and the environment in which the plant grows. As a general rule, check that the soil is moist, but that the pot is not over heavy – lift it before watering and you will soon get the idea of what it should feel like.

Do I really need to wash the roots?

If you have used a type of fertiliser, chemical or organic, you should clean the plants to prevent the taste of the weed from being affected by these substances. This is a very straightforward process. Two weeks before the harvest, you should thoroughly soak the plants with plenty of clean water – tap water is fine – or treated by reverse osmosis to entrain all the fertiliser remaining in the substrate.

How will I know when to harvest and get the best yield?

Between seventy to eighty days after the seeds were sown, you will be ready to harvest your buds. We advise not watering the plants about five days before harvest so that the earth is dry. You will notice that the buds are ready because the leaves turn yellow, and the colour of the trichomes of the resin will start to alter from white to dark apricot. Autoflowering cannabis plants have a built-in clock, and once they have passed ten weeks of life, they gradually fade away.

We recommend harvesting the plants on a slightly humid day if possible to prevent moisture from remaining inside the buds. The plants can be cut by branches that should be hung in a ventilated and dark place.

The final step is the manicure, which simply consists of trimming the leaves that surround the flower heads so that they look more attractive and, more importantly, so that they can develop deliciously complex aromas during drying.

Select the right strain for the best autoflower yield

Selecting the right strain from the right seed bank is one of the most important keys to success. Fortunately, there are plenty of autoflowers with a reputation for big harvests.

Curious to the autoflower yield? Check this blog and get the best tips to increase the autoflower strain yield both indoors and outdoors!

How Many Autoflowers Can I Grow In A Square Meter?

There are several things that help control the size of an autoflower, things like genetics, lights, and pot size make it possible to grow up to 6 plants per 1m2.

Almost all cannabis consumers that want to start cultivating their own cannabis want to fulfill their needs without having to spend too much. To do that, you have to make the most out of your grow space.

There are a number of things that can help you achieve that without having to spend more in another grow setup.

1. What Determines Plant Size In Nature?

When growing in nature, there’s nothing to limit a plant’s size. As they’re not growing in closed space, cannabis plants grown outdoors can grow even more than 3m tall.

That, of course, doesn’t apply to indoor growers.

Indoor growers have a limited amount of growing space, lights, nutrients, and medium. This can be seen as a bad thing, but this also gives us the ability to have complete control of our plant, being able to determine how tall, bushy, and even how much buds it will produce.

To do that, we adjust the type of light and size of the pot, we can also apply plant training and pruning to adapt the plants to what we have available.

2. What Determines Plant Size Indoors?

There are a couple of main factors that will determine the size our plant will grow. All of them can be adjusted to fit your preferences and can be adjusted according to your grow space and genetics you’re growing.


As you may know, Sativas grow tall and thin and Indicas grow short and bushy. This is one of the main factors that will affect how your plant grows. Even though nowadays it’s hard to find a pure Sativa or Indica, the hybrids most growers cultivate is a mix of pure Indica and Sativa genetics, and depending on the hybrid (it can be Sativa or Indica-dominant) it will grow shorter or taller.

A great example of a hybrid strain is our Orange Sherbet Auto which grows tall and bushy, showing characteristics of both Indica and Sativa lineage.

This is the first thing we should have in mind, a Sativa-dominant hybrid can grow more than 2m tall if no training is applied, while an Indica hybrid can reach up to 1.4m tall. So, if you’re looking to grow Sativa-dominant strains, you won’t be able to fit as much in your grow tent as if you were growing Indica-dominant plants.

Pot Size

Pot size is another very important factor. The amount the roots grow underneath will reflect directly in the size of your plant, so if you grow in a 5L pot your plant will be smaller than if you grow in a 10L pot.

Even if there’s a difference in the size of Sativa and Indica-dominant strains, pot size will decrease their overall size, as they won’t have space for the roots to grow.

For autoflowers, we recommend not going too big when choosing the pot size. Usually, an autoflower in an 11L pot will grow to its full height, as where an autoflower in a 5L pot will grow of medium height and in a 3L will grow small.

If you don’t have space issues, we recommend going with 11-12L pots so your plants can develop to their fullest.


Light coverage and intensity will also influence, not only in the size but also in the amount of resin and density of buds. When you grow too many plants in a small space, some will throw shade over others and the ones left underneath will not be able to develop properly.

That’s why you need to know the size of your grow space before buying the grow lights, this will ensure you get good coverage that can satisfy all your plants.


There are numerous plant training techniques, even though the methods vary, all of them have the same goal: adjust your plant to the growing space.

For autoflowers we recommend using low stress training (LST) techniques or using the Sea of Green (SOG) method to make the most out of your grow room.

3. How To Calculate The Area Of My Growing Space

Calculating the area of your growing space is fairly simple. To do this, we need a measuring tape to measure the length and width of our growing space. If we are planning to grow in a grow tent, we can find this information in the manual, but if it isn’t available, it is fairly simple to measure it.

So for example, if after measuring the length of our growing space is 1m and the width is 1m, we multiply both to get the total area, so: 1×1 = 1m 2 .

This applies to any size, even if our growing space is not a perfect square.

Another example is: length = 2 and width = 3, we would have an area of 2 x 3 = 6 m 2

This is extremely helpful because based on the area of our growing space we can calculate the potency of the light we will need and the number of plants we can fit in it.

Tip: If you’re measuring in cm, divide the result by 100 to have the area size in m 2 . For example: 200 x 400 = 800cm 2 , 800cm 2 ÷ 100 = 8m 2 .

4. Calculate Number Of Plants Based On Pot Size

For these examples, we will use a growing space of 1m 2 but you can do the math with your space’s measurements and you will have the same result.

Calculating exactly how many plants we can fit in our growing space can be difficult, this is a general guide and may vary depending on your growing environment.

Pots come in different shapes and sizes, and depending on the size, you will be able to fit several in your grow space. There’s no general rule but depending on the size of the pot you choose, you will limit the size of your roots, which will have a direct impact on the plant’s size.

Usually, we use the following table as a guide:

Pot Size Number Of Plants Per m 2 Plant Size
3L 25 25 cm
5L 18 60 cm
11L 9 Full plant height
15L 5 Full plant height
18L 2 Full plant height
21L 1 Full plant height

We can calculate the number of plants by multiplying the number of plants by the area of our growing space. So let’s say, our growing space has a width of 2m and a length of 3m, (2 x 3 = 6) the area of our growing space would be 6m 2 .

So, based on the table, we can have 5 plants on 15L pots in 1m 2 , so we multiply the number of plants by the area: 5 plants x 6m 2 = 30 plants. This means we can fit 30 plants on 15L pots in 6m 2 . You can adjust this to any size of growing space just by looking at the table and doing basic math.

Tip : If you really want to fit more plants in your grow space, we recommend using rectangular pots, this will prevent you from wasting space.

5. Calculate Light Potency Based On The Number Of Plants

There are two types of light fixtures: Light bulbs and LEDs.


With LEDs it’s impossible to calculate because the quality of the individual LEDs changes from one manufacturer to another.

The best thing is to follow the recommendations of the manufacturer that should be in the manual of the light fixture, if not, we recommend sending them an email asking for the information

If you tried everything and cannot find the information you need, you can follow the general rule: a 250W LED is equal to a 400W light bulb.

As said before, this is not always true and is only to be followed if you can’t find any other information about the LEDs you’re buying (almost all decent LEDs provide the area coverage and you shouldn’t worry too much about this).

Tip : Even though it’s not recommended because every LED is different if you still want to use this guide for LEDs, you will have to divide the number of watts by 1.6.

So if you were to need 2500W of light bulbs, in LED it would be 2500W ÷ 1.6 = 1562W of LED

Light Bulbs

Now, with light bulbs this is different and there indeed is a way to calculate the wattage you will need for a number of plants.

Let’s continue with the example we were following before. We рave a growing space area of 6m 2 and we already know we can fit 30 plants in it, what’s the wattage we will need.

Usually, we would need around 75W per plant, so by following the table we can calculate how many watts we would need for 30 plants in a 6m 2 growing space.

Wattage Number Of Plants
150W 2
250W 3 big or 4 small
400W 5
600W 8
1000W 13 big or 14 small

If you’re growing less than 14 plants, you can just look it up on the table. If you’re growing more like in the previous example, you need to multiply the number of plants by 75W.

So in our example, it would be 30 x 75w = 2250W.

This means we would need 2250W to grow 30 plants on 15L pots in a 6m 2 growing space.

6. How Can Plant Training Help Me In These Situations?

Even though there are a lot of plant training techniques, there are only a few that can be done on autoflowers without any problems.

The Tie-Down Method

With this technique, you will help the branches open up, allowing light to reach deeper resulting in multiple bud sites and denser buds. By doing this, you will be able to fit fewer plants in your grow space but you will get a bigger yield.

Continuing our example, if we had 6m 2 of growing space, we would be able to fit 30 plants. If you applied this method, that would be lowered to around 15 plants, depending on the pot size.

You can follow the table for a general guide:

Pot Size Plant Number Per m 2
3L 9
5L 6
11L 3
15L 2

In our example, we were using 15L pots so according to the table, we need to multiply the area by the number of plants, so it would be 6 x 2 = 12.

This means we could fit 12 plants in a 6m 2 area when applying the tie-down method. To calculate the wattage needed for those 12 plants, we have to multiply the number of plants by 75W, so 12 x 75W = 900w

Tip : If you need 900W and don’t have the space to have one 400W light bulb + two 250W light bulbs, you can use a 1000W bulb. This will not damage your plants and will only make them grow more vigorously

Obviously, this is approximate and you can fit a little bit more or less, depending on your skills and need.

Sea Of Green (SOG)

When growing in a Sea of Green, the number is higher than in the Tie-Down method and also higher than growing the plant without any kind of training. This is because plant training methods aim to control a plant’s size while also yielding as much as possible.

This method consists of slowly training your plants into an even canopy, allowing light to reach all bud sites equally.

The following is a general guide, and as said before, you can have more or fewer plants depending on your skills and need.

Pot Size Plant Number Per m 2
3L 16
5L 11
11L 8
15L 6

So, to recapitulate we had an area of 6m 2 where we would fit 30 plants (without training) in 15L pots that would need 2250W of lights.

In our example, we are growing in 15L pots so to calculate how many plants we can fit in a 6m 2 area of SOG, we have to multiply the area size by the number of plants per m 2 in 15L pots, resulting in 6×6 = 36 plants.

Meaning, we can fit 36 plants in a Sea of Green of 6m 2 , and to calculate the wattage, we have to multiply the number of plants by 75W, so 36 x 75w = 2700w

7. In Conclusion

There’s no exact number of plants you can fit in your grow tent, independent of the size. What will truly define that is a combination of your budget, genetics, equipment, and environment.

This guide will help novice growers figure it out, but it’s all a matter of preference.

If you are looking for plants to grow in smaller pots and haven’t decided what to grow in your next cycle yet, we recommend our Zkittlez Auto and Gelato Auto. Both of them grow between 40-100cm and will develop well with LST techniques.

There are several things that help control the size of an autoflower, things like genetics, lights, and pot size make it possible to grow up to 6 plants per 1m2