How Much Weed Can A 1000 Watt Light Produce?

How much weed can a 1000 watt light produce

One of the most popular questions that new growers ask is this: How much smokable bud will one plant actually produce?  For a very long time, cannabis growers considered light wattage to be the largest factor for maximized yields.  A 500 watt light, for instance, will produce less yield-per-plant than one double its power on average.  In this article, we’re going to answer the question “how much weed can a 1000 watt light produce?”.

How Much Weed Can A 1000 Watt Light Produce?

Short answer: Sadly, there is no simple answer to this question: the yield you get from a plant will vary based on a variety of factors, and the most important factor in lighting isn’t wattage, but PAR.  However, if you’re looking for a basic starting point using wattage only, you can estimate approximately .5 to 1 gram per watt.

Maximum Yield for 1000 Watts

When considering the way that light wattage effects yields, it’s important to keep in mind that lighting can only do so much.  There are many other factors that are equally important, so focusing on just wattage will only get a grower so far.

The rule of thumb, which (if we’re being honest) isn’t based on a scientific formula at all, is that you can expect to grow between .5 and 1 gram of usable bud per watt of light.  This standard comes from old-school growers, who didn’t have scientific data and used averages and word-of-mouth to determine what was “normal” for a grow space.

Now that we have more science on our side, we understand that there are far better ways to ensure big yields… but many growers still use this equation as a baseline to determine how well they’re doing with their plants.  Nowadays, if you’re really interested in growing the biggest, thickest, healthiest plants you can, you’ll want to consider a much wider set of variables.

Factors Which Effect Yield

Since most new growers are growing for personal use, it makes sense that they’d want to know how much they can yield from each plant. The cost of setting up a grow space and buying high-quality seeds can be very high – it’s a good idea to know approximately how many harvests you’ll need to do before you break even on your investment.

Unfortunately, there is no simple equation that can promise maximized yields. There are dozens of variables to consider, but today we’re going to focus on the top 5.


The idea that higher wattage = higher yield makes sense: you would expect more light to equal more food for your plant… and more food definitely equals bigger, fatter buds.  Unfortunately, higher wattage does not always equal more food for your plant.

PAR, which stands for Photosynthetic Active Radiation, is a scientific equation that determines how many of the lightwaves your light produces actually reach your plant and feed it.  That’s a really fancy way of saying that not all light is good light for your plant. Where wattage tells us how strong the light is, PAR gives us an accurate measure of how much edible food your plant is getting.

Plants need higher PAR values as they mature.  A seedling can thrive under a lower PAR value between 200 and 400.  Established plants that are still vegging will do best under a 400-600 PAR light, while flowering plants should receive a minimum of 600 PAR.

In general, lights with higher wattage should have higher PAR, but that’s not always true.  You can buy an inexpensive 1000 watt HPS that actually has a LOWER PAR value than a high-quality 600w LED.  When shopping for a grow light, it’s even more important to know the PAR value than wattage… if a manufacturer doesn’t disclose the PAR information for their light, reach out and ask!

Remember when you’re asking “how much weed can a 1000 watt light produce?” that the answer will vary depending on the PAR output of the light.

Grow Space

In addition to lighting, your grow space has a huge impact on your plant’s yield.  Size, height, temperature, and light leaking are all important to consider.

Size: Obviously, you’re going to get a much higher yield if you’re growing in a huge grow room (or, even luckier, outdoors) than if you grow in a tiny, Stealth grow box.  Luckily, there are some averages that you can keep in mind to help you decide which size grow space will benefit you most.

A stealth or tiny grow space will yield a maximum of 1 ounce per plant.
Smaller grow area (maximum of 2′ x 4′ or 3′ x 3′) will yield between 1 and 10 ounces.
A medium space (no larger than 5′ x 5′) can expect to yield 7 ounces to 2 pounds.
Large spaces (larger than 5′ x 5′) will see a good boost, yielding 2 pounds or more per plant.
Outdoor grow operations can produce between a few ounces and several pounds of usable cannabis per plant.


Did you know that a cannabis plant should continue growing its roots even into the flower cycle?  While root growth does slow significantly after the switch from vegetation, the roots still need space to grow.  Most plants will see root growth up until 2-3 weeks before they’re ready for harvest.

This is important because one of the best ways to stunt your plant’s yield is to put it in the wrong container.

When you harvest your plant and pull the roots from the container, you should find a significant amount of untouched soil.  Roots should make up no more than 60% of the container.  But since you generally can’t see how large the roots are, it’s a good idea to size up.  A 7-gallon container will increase yields over its 5-gallon counterpart every time.

Seedlings should be housed in a small container for the first couple of weeks, but should be moved to their permanent container once it has 2-3 nodes and seems to be thriving. (While the plant is small, it’s important to keep the watering inside, near the roots, since they’re still relatively short.)

The best containers also feature excellent drainage and breathability.

Low-Stress Training

Low-Stress Training, or LST, is a tool that many new growers don’t know about, but it’s an excellent way to increase your plant’s yields.  Essentially, LST is like an exercise program for your plant… it helps increase the ability for the plant to grow more, bigger buds.

There are a few kinds of LST, some of which are more complex than others, but all of them have the potential to drastically increase yields. Topping/Fimming can increase your yields by up to 150%, while scrogging or manifolding can double your plant’s yield.

It should be noted, however, that any kind of training places stress on a plant and can have negative results if done incorrectly. Growers who plan to use these tools should research thoroughly and be prepared for setbacks while they learn the techniques.


So far, all of these variables have been controllable for the grower, but there is one factor that you can’t control: strain.  Some strains naturally produce higher yields, while others may produce less.  There is no way to change the strain results for this one… if you’re looking for huge yields, you’ll want to choose a strain known for huge yields.

It’s also a good idea to avoid autoflower strains if you’re hoping for large yields.  Autoflowers, which are known for shorter lifespans, do not produce the same yields as their non-auto counterparts.  For instance, a White Widow seed will produce more than an Auto White Widow.  Even though the strain is the same, the yield will be different because of the autoflower.


In general, a light with higher wattage should produce a higher PAR value and, therefore, a better yield.  A 1000 watt light, on average, will produce more than its 500 watt counterpart.  As a basic rule of thumb, you can use the tried-and-true baseline of .5 to 1 gram per watt of light.

However, “how much weed can a 1000 watt light produce?” is really the wrong question to be asking. There are far better ways to maximize your yields, and many other variables that should be considered.  If you’re looking to ensure that you get the most bud for your buck, we recommend considering all aspects of your grow… including your grow space, lighting, container, and training methods.

What do you think? Have any tips or tricks that have worked to increase your yields?  If so, let us know in the comments… and, as always, thanks for reading!

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