Many new growers wonder, “How much marijuana can one plant produce?” or “How much will a 600-watt HPS yield?” Unfortunately, there  are no simple answers to these questions. Every grow is different and has different variables.

Whatever your reasons for growing are, you care about the yield.  You want to know what to expect, and that’s reasonable. I can’t predict your experience, but I can give some reasonable numbers to strive for.

This article will discuss everything there is to know about marijuana yields. I’ve added some common questions at the bottom, but if you have more, place them in the comments below this article.

Don’t want to read? Watch the video!

How much marijuana can you yield indoors?

Lights are of the utmost importance when you’re growing indoors. Experienced growers can produce about a gram of marijuana per watt of light (1 gram = 0,035 oz). So, a 400-watt HPS grow light can potentially translate to 400 grams or 14 oz of dried, usable cannabis.

Likewise, a grow room with 1200 watts of light can yield 1.2 kilograms or 42 oz of cannabis. Having the right equipment, adequate nutrient solutions, beneficial air quality, and other valuable factors is important for producing the highest yields possible. Making sure the plants have space to grow is also key.

Tip: make sure to download my free Grow Bible and learn how to maximize your yield

Average expected yield when grown indoors in soil

If you are using soil to grow indoors, you can expect somewhat less of a yield than if you’d grown hydroponically. This is because hydro growers can fully control the amount of nutrients their plants receive.

Although soil growing can potentially lower your yield, it also is easier to grow. This is because it not only creates a buffer for error, but it also holds nutrients within the soil. When growing in soil, there is room to make mistakes with pH and TDS and pay for it in yield. In terms of numbers, expect a maximum of 1 gram per watt. That means a 600watt lamp can produce 600 grams of marijuana or 21 ounces.

Yield even more when growing hydroponically

Growing hydroponically yields up to 20% more, as long as you do not make any mistakes. With hydroponic growing, there is no room for errors. You must be very careful about the TDS and pH levels because the roots are directly in water (and not soil) and incorrect levels can immediately affect the plants.

There are rarely small mistakes while growing hydroponically. Even the most minor error can ruin your yield. However, those who do it correctly will be rewarded. You can expect up to 1.2 gram per watt, which means a 600watt HPS lamp can give you 720 grams of marijuana or over 25 ounces.

The pictures below show that hydro plants and their roots grow faster than soil plants

Average expected yield per outdoor-grown  plant

Under perfect conditions, you can expect yields to extend to 500 grams or 17.5 oz of marijuana per plant. Space is a necessity (at least two meters) along with water, nutrients, and a dearth of pests and diseases. If you use containers, they should be at least 50 liters or 15 gallons in size.

It’s a good idea to germinate the seeds early on to allow the plants time to grow large. It’s best to germinate indoors where you can manage the humidity and the temperature for the seedlings. Again, 500 grams (17.5 oz) per plant is possible if everything goes as planned.

Aside from an adequate amount of sun, water, and nutrient quality, the actual genetics of the plant play a very important role. Seeds are vital, and you need to have some exceptional seeds at your disposal. Browse our cannabis seed shop to find the a strain that’s right for you. It all starts with genetics….

Yield does not have to be a guessing game

Want to predict your field before you grow?

Try using a cannabis plant yield calculator. This calculator by Yield O Rama lets you select your type light, the light intensity (lumen), your level of growing experience and your growing medium.

When using the yield calculator, keep in mind that an HPS grow light produces around 150 lumens per watt. For the exact amount of lumen that your bulb produces, check with the manufacturer.

There are some limitations:

You cannot adjust it for the strain, and it’s only for indoor grows, but it is still quite handy. Check out the cannabis yield calculator here.

You can also measure your yield after you harvest but, keep in mind….

Wet and dry weed does not weigh the same

Drying your weed slowly (10 to 14 days) in a climate controlled dark and dry place with a temperature of around 64 degrees will get you more weed in weight.

You will get about 20 % to 25 % out of your wet weed after drying, depending on the strain, the density of the buds and the way of drying. Only weigh the wet buds and not the whole plant.

Here’s an example:

Out of a well cultivated Sativa you will get approximately 20% -22% dry weed and from an Indica about 22% -25%. So out of one-pound wet Amnesia Haze you will get approximately 7.4 ounces and if you dry one pound of White Widow you’ll get about 8.4 ounces. At a street price of $ 7 (Oregon) or $12 (Texas) this is very good profit.

On the other hand:

You will end up with approximately 12.5% if you weigh the entire plant, including stems and leaves, while it’s wet.

Grow fewer plants to yield more marijuana

Indoor growing doesn’t bring a lot of certainty in terms of yield per plant. If you have only four plants per lamp, then you’ll yield much more than you would with a total of sixteen plants for every lamp.

Tip: make sure to download my free Grow Bible  for more information about setting up your grow room

Before deciding how many plants to grow, consider these facts:

• If you’ve only got 4 plants, your yield will be 25% less if one gets a disease or dies
• Vegetative growth lasts longer with only four plants. You should want to force flowering when the tips of the leaves are touching. If there are more plants, the leaves touch quicker
• Four plants are easier to manage than sixteen
• If someone catches you, you only have four plants to your name

Think about this:

Grow four plants using a 600-watt HPS lamp and yield about 150 grams or 5.0 oz per plant.

Grow sixteen plants under a 600-watt HPS lamp and produce about 37.5 grams or 1.3 oz of marijuana per plant.

But grow one huge plant per 600-watt HPS, and you could produce a pound of marijuana per plant!

Yield even more with screen of green

The Screen of Green (SCROG) technique is an excellent way to increase your yield. The idea is to top your plants and place a screen at 15 inches above your plants. When a branch grows 4 inches through the filter, tie it to the screen horizontally. Continue attaching the branches until you get a nice ‘blanket’ of tops.

Now, three reasons why growing with a screen of green technique increases your yield:

1. No wasted light
Any light that hits the floor or walls is wasted energy. With the SCROG method, you create a thick ‘blanket of leaves’ out of your plant that prevents light from being wasted, and instead forces it to be absorbed by the leaves.

2. All plants are the same height
When every plant is the same height, each will receive the maximum amount of light. With this method, there are no plants or branches in the shade, and you can place the lamp as low as possible, as long as temperatures don’t exceed 77 Fahrenheit.

3. No fluffy or soft buds
Because you prune the bottom branches that don’t grow through the screen, the plant doesn’t waste any energy on developing the small, soft buds at the base of your plant. (FYI, they never ripen.) Your plants also don’t waste energy on leaves and branches it doesn’t need. All of its energy goes to the top colas!

Here is a quick photo guide on how to SCROG:

I’ve used the screen of green method for many grows, and I’ve always been satisfied with the results. If you use it, your yield can increase by 10 to 20%. Read my article How to scrog for more information. You’ll need to master the basic grow skills of watering and pruning, first, however.

Lights make the difference for indoor grows

Does a 1000-watt HPS yield more than a 600-watt HPS? Well, not necessarily. While a 1000-watt HPS bulb produces much more light than a 600-watt bulb, a plant cannot convert all that light into energy. It will need more CO2.

TIP: Looking to buy seeds? Visit the ILGM seed shop

There is around 350-400 ppm of CO2 in the air. Indoor marijuana plants will use this CO2, combined with energy from the light to create sugars. If you grow in a closed grow room without an air inlet, the plants will use half of this CO2 within an hour and then slow down sugar production because CO2 levels are dangerously low. This is why you must continuously ventilate your grow room with fresh, CO2 rich air from outside.

With 350 to 400 ppm of CO2 in the air, your marijuana plants cannot create more sugars than the light from a 600-watt HPS bulb produces. So your yield will not be higher if you use a 1000watt HPS lamp under normal circumstances.

Tip: make sure to download my free Grow Bible and learn how to increase your yield with CO2

On the other hand, if you increase the CO2 levels, your plants will need more light, and in that case, a 1000-watt bulb can almost double your yield. It’s a large investment to buy the right equipment, but a 1000-watt grow light is worth it in terms of yield.

Want to learn more about CO2 and yield?

Here is an interesting article about CO2 and tomato plants.

Average indoor yield with CFL & HPS

Still, keeping the impact of CO2 in mind, there are some numbers that you can expect:

Imperial

1.5 to 2.0 oz average  (3.5 oz for advanced growers) with 200-watt CFL lamps in a grow cabinet measuring 3.5 x 1.5 x 6.5 ft.

3.0 to 5.0 oz average (9.0 oz for advanced growers) with a 250-watt HPS lamp in a grow cabinet measuring 3.5 x 1.5 x 6.5 ft.

4.5 to 9.0 oz average (14 oz for advanced growers) with a 400-watt HPS lamp in a 3.5 x 3.5 x 7 ft. grow room

5.0 to 10 oz average (21 for advanced growers) with a 600-watt HPS lamp in a 4 x 4 x 8 ft. grow room

9.0 to 18 oz average (36 for advanced growers) with a 1000-watt HPS lamp in a 5 x 5 x 8 ft grow room

Grow room with 1 x 600 watt HPS and Adjust a Wing reflector[/caption

Metric

40 to 60 grams average (100 for advanced growers) with 200-watt CFL lamps in a grow cabinet measuring 1 x 0.5 x 2 m

80 to 150 grams average (250 for advanced growers) with a 250-watt HPS lamp in a grow cabinet measuring 1 x 0.5 x 2 m

100 to 250 grams average (400 for advanced growers) with a 400-watt HPS lamp in a 1 x 1 x 2.5 m. grow room

150 to 300 grams average (600 for advanced growers) with a 600-watt HPS lamp in a 1.2 x 1.2 x 2.5 m. grow room

250 to 500 grams average (1000 for advanced growers) with a 1000-watt HPS lamp in a 1.5 x 1.5 x 2.5 m. grow room

LED grow yield

There has been much said about LED lights, with many manufacturers claiming super high yields, but I haven’t seen them yet. I’ve tried a 300-watt LED grow two years ago and generated less than half of what I usually produce. Many of my friends also haven’t received desired results.

An interesting fact is that commercial tomato growers haven’t switched to LED. For me, that’s a sign that they’re no better or more economical than HPS grow lights. With LED, the light intensity isn’t as strong as with HPS lights. Instead, the spectrum is more important. Read the science behind LED on wikipedia.com

So, I can’t tell you how much you will yield with a LED grow light. If anybody has some results, please share them in the comments. I can confirm that LED lights produce a lot less heat compared to HPS lights. This will cause the plant to evaporate less water, changing the water and nutrient requirements for growers.

You can save money by growing marijuana

A store-bought marijuana plant will cost around $10 to $15. It will be a clone of around 5 inches tall, and they’re only available in the states that have legalized marijuana. High-quality marijuana seeds cost between $8 and $15. They’re available all over the internet and of course in my webshop 😉

Clones for sale for $15,- each at La Conte’s clone bar in Denver.

But these figures do not cover the cost of producing weed. You need to buy equipment, nutrients and keep an eye on the electricity and water costs. Below are some estimates; read my article on costs and revenues for more details.

TIP: Looking to buy seeds? Visit the ILGM seed shop

For example:

Growing 5 marijuana plants in a 2×2 foot grow tent with 2x100watt CFL will cost you around $1000 per year and yield 0.25 pound of marijuana per harvest. With 4 harvests per year, each marijuana plant costs about $50.

Growing 5 marijuana plants in a 4x4foot grow tent with a 600watt HPS light will cost you around $2000 per year and produce 1 pound of marijuana per harvest. With 4 harvests per year, each marijuana plant will cost around $100.

The basic equipment like filters, timers, and exhaust fans are very expensive. The price difference between a setup for 2 or 4 lights is only 20% higher, but the yield doubles. Again, learn more about the revenues and costs of growing marijuana on my blog.

You could be saving money, especially if you yield a pound per plant indoors.

Want the most yield for your effort? Grow one plant.

If you want to grow a one pound marijuana plant, you need a 4 x 4 foot grow tent or other similar sized space, and a 600 – watt HPS grow light. Under ideal circumstances, a 600watt light can produce well over a pound of cannabis. If you limit your grow to just one plant, it can produce over a pound of weed. The picture below shows one plant under 600watt

One plant under 600 watt can produce a pound of weed. Picture by: Rolling Stoned

You have to prune and trim your plant a lot otherwise it will grow through the ceiling. Scrogging is the way to go to cover 10 square feet with one plant.

Growing a one-pounder is a fun project, but there are some downsides. You need to veg the plant for very long until the entire floor is covered with leaves, so no light goes to waste. Plus, if your plant gets sick or anything, you don’t have replacements. But it can be done!

Want to feature your 1-pounder indoor plant on our blog? Send me a picture!

Whether you are growing indoors or out, you can effectively plan for how much weed you’ll yield. In some cases, you can even grow a pound per plant. It’s all about planning your grow setup and using the right grow techniques. You can predict your yield with a calculator or wait and weigh it after the harvest. However you decide to grow, you’re likely to save money over buying it at a dispensary.

Robert Bergman

Got Questions?

What about fluorescent lights? Can I use them throughout my grow?  You can, but you will not yield as much. They work best during the vegetative stage. For more on fluorescent lighting read these articles.

Are there any other ways to increase yield? Yes, there are other techniques that can increase optimal yield. Read these articles to learn more.

I want big yields, but I have a small space, what do I do? You can try a variety of plant training techniques such as scrogging as well some other tips mentioned in this article.

Are the estimates in this article reliable? Your final yield depends on a variety of factors; too many to develop a reliable equation. The estimates in my article are the best-case scenarios for the average grower.