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Basics of Growing Autos in Soil from Seed to Harvest

Check out the basics for growing Autoflowers in soil, from seed to harvest!
1 year ago
7 min read
Basics of Growing Autos in Soil from Seed to Harvest


An autoflower is a special type of cannabis created by mixing the genetics of the Ruderalis with a traditional cannabis plant. Over the years, autoflowers have become stronger and sturdier enough to be grown by both commercial and home growers.

The biggest difference between autoflowering and photoperiod plants is that autoflowers begin to flower irrespective of the light provided. Therefore, an 18/6 light cycle from the very beginning until the end will work perfectly. Although autoflowers are easy to grow, it’s best to familiarize yourself with the basics before you start.

So, here’s a step-by-step guide to help you through the entire process.

What you’ll need:

  • Good quality autoflowering Seeds

  • Potting soil containing equal proportions of peat moss or coco peat/coir, compost, perlite, vermiculite (optional) or a commercial potting mix

  • Aerating containers that are at least 5-8 gallons

  • Super powerful artificial lights like HPS or LED or at least 12 hours of sunlight if you plan to grow outdoors. Use CFLs during the seedling stage

  • Nutrients for vegetative and blooming phases.

  • Grow Room to house at least 1 plant.


fastbuds tap root

It’s pretty easy to germinate cannabis seeds. You can sow the seeds directly in the pot, but if you don’t have a lot of experience or are impatient like the rest of us, soak the seeds in plain water for 24 hours. It’s common to see a tiny tap root after a day of soaking but it’s alright if you don’t see them.

Many growers use nail files to gently scratch the surface of the seeds, but do not do this if you’re fairly new. A scratch on the seed coating allows water to penetrate the shell and the seed develops a taproot faster. Place the seeds in moist paper towels for 2-3 days until you see long tap roots. The next step is to plant seeds in their final containers and wait for them to push through the soil.

Here’s a quick video to help you with germination:

Week 1

fastbuds cannabis seedling

The first week is extremely crucial for autoflowers. It’s important to NOT use any fertilizers in the seedling stage since the plants are very tender. You risk burning them, and a single mistake now might prove very costly later. The seedling will have two cotyledons (sometimes 3) that are almost round in shape when they just appear.

There are various products that can be used on seedlings, but they are not necessary because they will be fine even if they are left alone. At this point, you can use CFLs or fluorescent lights to ensure that the seedlings don’t burn under powerful lights.

However, many growers wing this by adjusting the distance between the lights and the seedlings so that a single LED light is used for the entire cycle from seed to harvest. Water the seedlings sparingly only when the pots are almost dry. Overwatering or under-watering seedlings can either stunt or kill them, so it’s recommended that you water only when the plant needs it.

The seedlings develop at least two leaves apart from the cotyledons at the end of week 1.



Week 2

fastbuds GG by BigdaddyK

You can use nutrients at quarter strength once the seedling is comfortable with at least two leaves. Continue using nutes at quarter strength at this point, but regulate the pH and maintain the range from 5.5 to 6.5 at all times. Some growers use half strength but it depends on how big the plant has grown.

If you see more than 3 to 4 nodes on week 2, use nutes at half strength. Monitor the plants carefully to detect any burn or deficiencies. As always, water the plants only when the pot is almost dry. Shift the lights closer to the plant if it starts growing too lanky. 

Week 3

Fastbuds Gorilla glue BigDaddyK

Now that the plant is 15 days old, use the nutes at full strength. Some plants like Gorilla Glue, for example, need a lot of nutes whereas others may not require too much. “Less is more” when it comes to nutrients in autoflowers, so use nutrients at full strength only if the plants have responded positively until now.

Gorilla Glue Auto
Gorilla Glue Auto
Gorilla Glue autoflowering
9-10 weeks
Very High
Learn more

Autoflowering plants bounce back quickly if they receive fewer nutrients; however, they get stunted if an overdose occurs. Watch the plants carefully for any signs of deficiencies and water them as required.

If the plant has more than 4-5 nodes, you can “Top” it or use the FIMming technique. Both methods require you to cut the top of the plant to allow more colas. The lights must be at least 20 inches away from the top of the plant; however, it’s okay to reduce it to 18 inches especially if the plants are stretching.

Week 4

fastbuds GG week 4 by fastclub

Now that the plant is a month old, it grows very vigorously if it’s healthy. Use nutrients at full strength now. It’s a good idea to start training techniques like LST at week 4, but if the plant has grown more than expected, you can start at the end of week 3.

Most autoflowers display their sex on week 4, but some may not do that. Continue watering the plants and feed nutrients meant for the vegetative stage. If you’re using a two-part commercial nutrient solution, only the “Grow” part along with micronutrients must be used.

Even if the pistils show up, it’s recommended to not use bloom nutrients since we need to help the plant focus more on the growth rather than producing flowers.

Week 5

fastbuds week 5 GG by fastclub

You’ll see more pistils now, but continue using the “Grow” or part or nutes meant for the vegetative stage. To put it simply, anything that contains a tad more nitrogen will work well. Most nutrient companies will advise you to use bloom nutes now, but since bigger plants produce more yields, it’s important to keep using more nitrogen.

Water as usual and check for deficiencies. It’s also a good idea to check the undersides of leaves to detect spider mites. Of course, this has to be done right from week 1 to prevent any pest attacks. Start preparing for training techniques like ScrOG to generate more yields.

Week 6

fastbuds week 6 GG by fastclub

The plant may begin stretching like crazy now. This is when you can shift to bloom nutrients since pistils keep shooting everywhere. Always remember to use products like CalMag or anything that supplies good amounts of Calcium and Magnesium.

You should use CalMag from the very beginning, but since the plant is preparing its buds now, micro and macronutrients are even more essential. Switch the lights to flowering mode if there are separate switches. The plants need more red light during the flowering stage.

Week 7

fastbuds week 7 gg by fastclub

Continue using bloom nutes during week 7. Other products meant for buds can be used right from week 6. Now is the time to defoliate the leaves if the canopy is too tight. The lower parts of the plant need light too, so manage the plants with training techniques. The plants stop stretching and focus completely on buds now.

Week 8

fastbuds GG week 8 by fastclub

Water as required and just keep the plants happy. Depending on the strain, your grow tent will smell aromatic or skunky. It’s best to use carbon filters to mask the smell as best as you can.

Week 9

Fastbuds GG week 9 by fastclub

The leaves may begin to yellow slightly but they shouldn’t fall off entirely. It’s natural and you can continue to use bloom nutrients and other supplements.

Week 10

fastbuds week 10 Gorilla Glue by Fastclub

It’s important to check the color of pistils now. If they are all still white, proceed to use nutrients but if they are turning amber, stop supplying all nutrients. You can start flushing the plants at this point. Flushing is nothing but providing a lot of water to remove salt buildups in the soil.

For instance, if you’re using a 5-gallon pot, start flushing with 15 gallons of water to force the nutes to leave the soil. The leaves will be mostly yellow now but that’s completely expected. Flushing also improves the taste of the buds to a large extent.

Some growers don’t bother flushing, but it’s necessary to prevent a harsh taste when you smoke the buds. Of course, curing the buds will take care of the harshness, but flushing shouldn’t be ignored. Continue flushing for at least 2-3 days to eliminate the salts.

Week 11

Harvesting the buds has a lot to do with personal choice. For example, some growers harvest when at least 60 percent of the trichomes are amber in color. Waiting too long until all trichomes turn amber will produce buds that are very sedative.

On the other hand, harvesting too early when most pistils are white will give you buds that are very psychoactive. Therefore, wait until 60 percent of trichomes are amber. To be sure, use a magnifying lens to check whether 60 to 70 percent of the trichomes are cloudy.


fastbuds GG harvest by bigdaddyk

Go ahead and harvest the buds using clean and sterilized scissors. Allow the buds at the lower parts of the plant to continue growing if they are too small. Harvesting sequentially gives you a better yield. Drying and curing the buds is a very important part of the process. Even if you’ve flushed the plants, you cannot skip curing it because curing breaks down the THCA into THC.

So, that’s pretty much how you grow autoflowers from seed to harvest. It’s obvious that you need quality seeds to go through the cycle without any hassles. Take a look at our catalog to find what suits you and get growing today!