Top 8 Best Strains to Grow in a Greenhouse: 2021 Comparison

If you have a greenhouse, you likely have one of the best places on earth to grow cannabis. In fact, growing cannabis in a greenhouse can increase yields, providing you don’t let it get too hot. With a good setup, you’ll have an ideal environment to grow many strains. However, it can always get better. The best strains to grow in a greenhouse excel in warm temperatures and high humidity.

Of course, your best greenhouse weed strain will heavily depend on your location. For example, no matter what heating or cooling you use, outside temperatures will always impact the greenhouse.

The table below shows a quick comparison of all the best strains to grow in a greenhouse that we researched:

StrainsFlowering Time (Weeks)Yield (Per plant)Indica/Sativa
Gorilla Glue Feminized8500-600g50% Indica/50% Sativa
Super Silver Haze Feminized9-11425g10% Indica/ 90% Sativa
Northern Lights Auto Feminized6-7450g70% Indica/10% Sativa/+/-20% Cannabis Ruderalis
Trainwreck Feminized8-11600-70090% Indica/10% Sativa
White Widow Feminized8-9900g60% Sativa/40% Indica
Jack Herer Feminized8-9500g40% Indica/60% Sativa
Critical Mass Feminized8-9500gIndica-dominant
Blue Dream Feminized6-7700-850g70% Indica/30% Sativa

Importantly, these yields are based on ideal conditions. Your own grow may vary based on care, temperature, and nutrition. For example, you might see a much larger yield with training techniques and good feed. Optimizing your greenhouse setup for your location and the strains you want to grow will always be an important step. 

We’ve listed the results of our greenhouse strain growing research and the characteristics profiles of each seed below. You’ll be able to see the benefits of their grow and some general information about the bud as well.

*Strains are ranked in no particular order.

1.      Gorilla Glue Feminized

Gorilla Glue is dense, sticky, and dank. This strain wants training, good light, and high humidity. That makes her a perfect greenhouse grow.

In addition, these sticky, trichome-covered buds have won awards. Gorilla Glue is popular for growers and smokers. Plus, with up to 600g per plant – this is not a lightweight producer.

Additionally, Gorilla Glue performs well in most mediums. If you want to fit in more plants, use a hydroponics setup. This is also ideal, considering she can be a little picky about the nutes. When you do feed, make sure you get it right.

Essentially, this plant is a great choice for slightly more experienced growers. That aside, even with no extra care or training, her massive central cola will deliver more than you asked for you. Plus, with just 8 weeks between veg and chop, she’s fast. Gorilla Glue finishes in mid-October if you don’t use light restriction.

  • THC Levels: 26% (high)
  • Indica/Sativa: 50% Indica/50% Sativa
  • CBD Levels: 1% (Low)
  • Yield: (Grams per square meter) 500g / 500-600g per plant
  • Flowering Time: 8 weeks/ Mid-October
  • Plant Size: 100cm / 39 inches
  • Optimal climate: Warm & humid
  • Grow difficulty: Medium
  • Genetics: Gorilla Glue #4 x Cannabis ruderalis
  • Effects: Relaxed, Happy, Uplifted, Energetic
  • Flavors/Aroma: Pine, Diesel, Earth, Herbal, Fruit

2.      Super Silver Haze Feminized

With her frosted buds and sticky leaves, Super Silver Haze is a classic. Plus, her smooth highs and earthy lemon bud, she tastes amazing. Super Silver Haze is incredibly popular the world around. And, the temperature and humidity tolerance she’s famous for make Super Silver one of the best greenhouse marijuana seeds available.

If you want a good yield, you’ll want to use some training. Super Silver Haze has massive central colas. Keep the big top leaves down. Plus, use a trellis or a screen of green technique to take weight off the branches or they will snap. This strain is a little fragile, so don’t put her next to a walkway.

For best results, use large buckets. Feed her in stages to ensure good growth. Then, prune back the top leaves as buds start to mature. Super Silver Haze will finish in mid-October. Additionally, this Sativa-dominant strain takes a bit longer to veg. Start in April for a mid-October finish.

  • THC Levels: 18% (Medium)
  • Indica/Sativa: 10% Indica/ 90% Sativa
  • CBD Levels: Less than 1% (Low)
  • Yield (Grams per Square Meter): 450-500g or 425g per plant
  • Flowering Time (Weeks): 9-11 weeks or Mid-October
  • Plant Size: 170-230cm / 67-90 inches
  • Optimal Climate: Moderate and humid
  • Grow Difficulty: Easy
  • Genetics: Northern Lights, Haze, Skunk #1
  • Effects: Creativity, Energy, Euphoria, Happiness, Uplifted
  • Flavors/Aroma: Earthy, Herbal, Lemon, Skunk

3.      Northern Lights Auto Feminized

Greenhouses give you the freedom to grow year-round and this Northern Lights Auto makes that dream come true. Without relying on light, you can get in as many crops as you want. Northern Lights Auto is incredibly high yield and reliable for an autoflower.

Plus, she delivers the classic, Northern Lights experience. You get big buds with moderate THC. At the same time, you’ll go soaring on a calming, soothing high every time you smoke. That’s probably why this strain remains one of the most popular in the industry.

Plus, Northern Lights Auto is easy. Don’t prune or train her. Just keep the big top leaves down and you’re good to go. You’ll get 450-500g per square meter of premium weed just 6-7 weeks after she starts to flower. Plus, this strain is short. Northern Lights auto will easily fit into even a small greenhouse, giving you plenty of room for more plants.

  • THC Levels: 15% (Low)
  • Indica/Sativa: Indica/70% Indica/10% Sativa/+/-20% Cannabis Ruderalis
  • CBD Levels: Less than 1% (Low)
  • Yield: (Grams per square meter): 450-500g
  • Flowering Time (Weeks): 6-7
  • Plant Size: 120-170cm / 47-55 inches
  • Optimal climate: Temperate Coastal
  • Grow Difficulty: Easy
  • Genetics: Cannabis Ruderalis x Northern Lights
  • Typical Effects: Strong, body high, calming, body buzz
  • Taste & Smell: Pepper, Spice, Fruit, pungent

4.      Trainwreck Feminized

Trainwreck is famous for her hard-hitting, frontal-lobe highs. But growers also love her fluffy buds covered in dense trichomes. Of course, Trainwreck’s intense, floating highs have remained a grower’s favorite as well – but you’ll have to grow her first.

This strain also loves being in a greenhouse. More light and higher humidity mean more weed. Trainwreck grows fast, big, and reliably. She’s also a great choice for hydro grows. Additionally, you can increase yield with Screen of Green or Sea of Green training. Low stress training is also a great idea. Plus, this strain can get huge, so you’ll want to control height for your greenhouse.

It’s also important to consider that some states benefit from using lights. If your greenhouse doesn’t get enough direct light, you’ll want to supplement. However, doing so will get you up to 700g of weed per plant.

Trainwreck used to be available via clone only. Today, she’s been reverse engineered by several seed breeders. Therefore, any seeds you get are not the original strain.

  • THC Levels: 16-21% (Medium)
  • Indica/Sativa: 90% Indica/10% Sativa
  • CBD Levels: Less than 1% (low)
  • Yield: (grams per square meter): 400-600g/600-700g per plant
  • Flowering Time: 8-11 weeks
  • Plant Size: 250-450cm / 98-177 inches
  • Optimal climate: Sunny and temperature
  • Grow difficulty: easy
  • Genetics: Mexican, Thai, Afghani landrace
  • Typical Effects: Happy, Euphoria, Uplifted, Creative
  • Taste & Smell: Lemon, Pepper, Herbal, Pine

5.      White Widow Feminized

This coffee shop star will perform almost anywhere. That’s likely why this long-time favorite is a perfect greenhouse strain. She’s fast, adaptable, and loves humidity. Of course, many growers also appreciate White Widow’s moderate sizing, which makes it easier to fit her into many grow houses.

Plus, White Widow just delivers. You get big buds and up to 900g per plant. Flowers are sticky, covered with white trichomes, and deliver an amazingly heavy high. There is, after all, a reason White Widow is on every coffee shop menu in Amsterdam.

Additionally, White Widow is as easy as they come. She benefits from light pruning but other than keeping down the top leaves, it’s not that necessary. Feed is also necessary. Other than that, you can choose almost any setup, dirt, hydro, etc., and get amazing results.

  • THC Levels: 20-24%
  • Indica/Sativa: 60% Sativa/40% Indica
  • CBD Levels: Less than 1% (Low)
  • Yield (Grams per Square Meter): 450-500g/900g per plant
  • Flowering Time (Weeks) – 8-9 weeks/End of October without light restriction
  • Plant Size: 150-190cm / 59-60 inches
  • Optimal Climate: Temperate and sunny
  • Grow Difficulty: Easy
  • Genetics: Brazilian Sativa landrace/South Indian indica
  • Effects: Uplifting, Relaxation, Energy, Happy
  • Flavors/Aroma: Fruit, Pine, Pungent, Sweet

6.      Jack Herer Feminized

If you’re looking for one of the world’s most popular greenhouse grows, Jack Herer is it. This strain is nothing short of legendary. Whether that’s for its ease of growth, massive yield, rich lemon flavors, or the incredible highs is really up to you to decide.

Jack Herer makes a great greenhouse grow. Outdoors, you’ll get a slow veg period followed by massive flowering. In your greenhouse, with controlled humidity, the entire process goes much more smoothly. Of course, Jack shoots up to well over 10 feet. You’ll want to use training and maybe Screen of Green to keep her to a manageable size. But, just 8-10 weeks after veg, you’ll harvest up to 500g per plant of some of the best weed you’ll ever grow.

Plus, with an end-of-September finish, Jack Herar is a great choice to grow without light restriction.

Buds are sticky, incredibly sticky, and great for extracts and smoking. This is also covered with trichomes, famous for its rich terpene count, and overall just a good grow.

Of course, you’ll have to check which phenotype you have. Some variations of this strain flower faster than others. But, you’ll see few differences otherwise.

  • THC Levels: 20% (Medium)
  • Indica/Sativa: 40% Indica/60% Sativa
  • CBD: Less than 1% (Low)
  • Yield: (Grams per square meter) 450-500g / 500g per plant
  • Flowering Time: 8-9 weeks/Late September
  • Plant Size: 200-300cm / 79-118 inches
  • Optimal Climate: Humid & Sunny
  • Grow Difficulty: Medium
  • Genetics: Shiva Skunk x Haze x Northern Lights #5
  • Typical Effects: Creative, Energetic, Euphoria, Happy, Uplifting
  • Aroma/Flavors: Pepper, Earth, Lemon, Pine, Spice, Wood

7.      Critical Mass Feminized

Critical Mass is one of the most popular greenhouse grows in the world. That entirely relates to the fact that she produces 650-700g of high quality weed per square meter, but who’s checking. Critical Mass is also relatively easy to grow.

Of course, greenhouse growers need to ensure good air circulation. Use fans and vents for the best results. Critical Mass may be high yield but her dense buds are prone to mold and top rot. That means keeping humidity down and keeping air moving.

Otherwise, you’ll want to invest in a trellis. This strain also responds very well to screen of green. But, big central colas can snap stems if you’re not careful. Give her good support, keep the air moving, and make sure she gets enough light, and you’ll get a massive yield in 8-9 weeks from veg.

  • THC Levels: 18-24% (high)
  • Indica/Sativa: Indica-dominant hybrid
  • CBD: Less than 1% (Low)
  • Yield: 600-700g per square meter/500g per plant
  • Flowering Time: 8-9 weeks
  • Plant Size: 150-165cm / 59-65 inches
  • Optimal Climate: Arid, sunny, temperate
  • Grow difficulty: Medium
  • Genetics: Afghani x Skunk #1 (some variations are Afghani x Big Bud)
  • Typical Effects: Happy, relaxed, sedative, body high
  • Aroma/Flavors: Sweet, Earth

8.      Blue Dream Feminized

Blue Dream is maybe the best greenhouse seeds strain for most of the U.S.

Why? Grown in a normal climate, you’ll get 400-700g of good quality weed. On the other hand, if you add high humidity, more light, and good conditions – you can bump that as high as 900g and increase trichome and crystal count. Blue Dream is a beautiful plant almost anywhere, but given good conditions, she truly thrives.

This 70% sativa strain can get big. You’ll wait 6-9 weeks for flowering. You can use that time for low stress training or screen of green. Don’t get too aggressive with trimming though, Blue Dream delivers top quality trim, perfect for extracts.

Of course, if you don’t’ care about the trim, Blue Dream offers some of the biggest buds you’ll get anywhere. That does mean keeping air circulating near the end of flowering. Otherwise, there’s not much to worry about. Just provide the light, nutes, and warmth, and Blue Dream will do the rest.

Plus, if you grow her during her natural photoperiod instead of using light restriction, you’ll get insanely dark purple leaves and buds as temperatures start to cool.

  • THC Levels: 20% (Medium)
  • Indica/Sativa: 70% Indica/30% Sativa
  • CBD Levels: Under 1% (Low)
  • Yield (Grams per square meter) 500g, or 700-850g per plant
  • Flowering Time: 6-7 weeks, mid-October
  • Optimal Climate: Coastal Mediterranean
  • Grow Difficulty: Easy
  • Genetics: Blueberry Ice X Haze
  • Effects: Cerebral, Euphoria, Stress Relief, Body high
  • Flavors/Aroma: Sugar, Berries, Lemon, Herbal

Greenhouse Cannabis Growing Advantages

Growing weed outdoors allows you to get bigger, better plants with a higher output. On the other hand, growing indoors gives you more protection from neighbors and from pests. Plus, you get more protection from the environment. Growing in a greenhouse gives you something of the best of both worlds. Your weed plants are enclosed and safe. And, you get near full control over humidity, temperature, air circulation, and light. A good greenhouse setup can also adapt to the seasons, so you use fans and light restriction in the summer. Then, you can turn on lights and heaters when winter rolls around for year-round production.

Greenhouse weed quality also tends to be stellar. Your greenhouse protects plants from weather, storms, and insects. Therefore, you’ll have minimal damage to buds and to plants. Plus, with controlled dirt and nute sources, you know what your plant is feeding on at all times.

Feminized Seeds for Greenhouse Growing

Most growers moving to greenhouses want to grow as fast and as reliably as possible. While that’s not always the case, it likely is. Feminized seeds make this as reliable as possible by ensuring that every plant is female. That is, of course, unless plants are exposed to high stress during germination. While feminized seeds have some drawbacks in terms of slightly weaker growth and yield, you’ll spend less time sorting through plants for males. And, with many states only allowing 3 juvenile plants at once, that can save you an entire month if you end up with male seeds.

Next Steps:

If you have or are planning to invest in a greenhouse, it’s a great place to put your cannabis plants. Of course, you’ll still have to make sure neighbors (and the public) can’t see inside. Plus, you will have to invest in temperature control to keep the greenhouse ideal year-round. Otherwise, greenhouse grows can produce some of the best weed you’ll have in your life. This list of the best strains to grow in a greenhouse should be a good place to start. You can follow up with your own research for your local conditions and, of course, the type of weed you like to smoke.