How to Grow Hemp Seeds Indoors

Medically reviewed by Alexander Tabibi, MD
October 12, 2021
best supplies to grow weed indoors
best supplies to grow weed indoors

Nowadays, the variety of cannabis plants available on the market can make you utterly speechless. Unfortunately, at the same time, with the hemp plant being more or less legalized throughout different states (depending on the state), there are still zero FDA regulations on this product and in the hemp industry overall. Hence, buying hemp-derived products is a question of trusting the manufacturer to be responsible for what they are creating.

As a result, but not only for this reason, of course, indoor hemp farming is becoming more and more popular as more and more people want to be sure what exactly they are ingesting. For others, growing hemp plants indoors can become a nice hobby as long as it is legal.

Here we will look at the procedure of how to grow hemp seeds in a pot which is fairly simple if to put it that way, and the results will be fantastic. Here are some steps to help you start growing hemp indoors.

This post is intended as information and for general knowledge only. It is not a substitute for medical advice, diagnosis, or treatment. It is recommended that you consult a healthcare professional before introducing cannabinoids into your daily routine, especially if you have been diagnosed with any medical conditions or are under any medication. It is not recommended to drive or operate any machinery when using cannabis- or hemp-derived products. Use responsibly!

Preparing Your Pot

Before you get started, you will need to prepare your pot. Begin by washing the pot thoroughly. Then, if you are using a container that is not meant to be a plant container, you will need to cut a hole in the bottom. You will want to be able to look inside easily and avoid any dirt that could get stuck in the bottom. Once you have a suitable pot, you need to cover it with a clean, damp towel or plastic wrap. 

Choosing a Plant

Now that your plant is ready, you should get some seeds. It is essential that you understand beforehand that the seeds that you are buying need to satisfy the needs of yours: whether you are going to grow the hemp plant for the flowers or for the hemp fiber.

Male and Female Plants

The cannabis plant, when growing, can develop in either males or females. Fertilized plants, that is, when male pollen gets in the female buds, create seeds. When female plants are kept separately from males and are not pollinated, they develop bigger and “fluffier” buds. 

Thus, if your needs are to get only nice hemp flowers, you may buy do-called feminized seeds that will develop in only female plants. If you seek other purposes but flowers, then it does not matter much. 

It is worth knowing that some plants might develop both male and female flowers when exposed to a stressful environment.

Germinate Hemp Seed

Growing the cannabis plant indoors allows you to control its environment fully and manage its flowering. To succeed, follow these simple steps.

Germination would be your first step, which is technically the sprouting of a seed into a smallish plant. Those who grow some other plants at home are definitely familiar with this term.

  1. First, you would need to pre-soak your seeds for 9–12 hours to help your hemp seedlings perform best.
  2. The next step would be to plant these seeds 1 inch into moist soil. Many shops nowadays offer special starter kits and starter soil mix to promote growth. 
  3. At this step controlling the temperature is important – it should be around 65–70℉. Having a thermostat will help you monitor and control the temperature.

Planting the Hemp Seedlings in a Pot

After successful germination, when you see the roots at the bottom – it would be a sign for you to plant it in a 5-inch container, using a special soil mix to help your plant accommodate faster. You also would need special nitrogen-rich fertilizer to achieve better results.

Now, a good quality pot is also of great importance. Modern shops provide a rich variety of pots for everyone to find something to their liking. You will need to wash it thoroughly to remove any dirt or impurities. Having done that, fill the pot with potting soil. This is also important to mix your soil with plenty of water-soluble nutrients. These nutrients help the seedlings grow. You can buy this at every garden shop.

Transplant Hemp Seedlings

The last transplantation to be made is when your hemp grows out of its 5-inch container. Once again, you are planting hemp in a bigger container with nutritious soil to help it thrive.

Grow Vegetative Hemp

Vegetative Hemp is the one grown not for the flowers. There are several factors to think of:

  • Temperature. Younger plants require higher temperatures, around 70–82℉, while older plants would require 60–80℉.
  • Humidity is another important factor and should be kept at the rate of 40–70%.
  • Light is a key factor in stimulating flowering. When you need to avoid flowering, keep the light on for 18–24 hours a day. This will enable the growth of your vegetative hemp transplants and their leaves, and if the lamps are placed a bit upwards, the plants will also go a bit higher.
  • Watering. Hemp soil needs to be always moist but not too soggy, with a certain balance. A nice comparison for the relative point would be a squeezed sponge.
  • Fertilizing. Plants, obviously, need a bit of help to thrive. NPK ratio in fertilizers stands for the percentage of the volume of Nitrogen (N), Phosphorus (P), and Potassium (K). For a vegetative plant, the ratio should be 3:1:2.

Do not get frustrated or disappointed when only starting out; you will, for sure, get used to these procedures, maybe experiment a bit, and succeed eventually.

grow flowering Hemp

When you aim to have as many fluffy hemp flowers, then this guide is for you:

  • Temperature. Younger plants require higher temperatures, while mature plants will require a cooler environment like 68–77℉.
  • Humidity is another important factor, it should be kept at the rate of up to 70%, but when flowering, it should go to the level of 40–50%.
  • Performing hemp indoor growing, lighting is a crucial factor in stimulating flowering. Longer night periods affect flowering the most. So after 30 to 60 days of usual vegetative growth, turn your lamp off for 12 hours, and then keep it on for another 12. When turned off, plants must be in complete darkness.
  • Watering. Hemp soil needs to be always moist but not too soggy, with a certain balance. A nice comparison for the relative point would be a squeezed sponge. For a mature plant, watering can be less frequent. The main idea is not to let your plant dry out. 
  • Fertilizing. Plants, obviously, need a bit of help to thrive. NPK ratio in fertilizers stands for the percentage of the volume of Nitrogen (N), Phosphorus (P), and Potassium (K). For a flowering plant, the ratio should be 1:3:4.

Another critical factor is providing air circulation to avoid pests and fungal diseases. Go ahead and try out these techniques for the best results.

Caring for the Hemp Seedlings

Caring for your hemp seedlings is no different than how you would care for any other plant. You want to water them once in the morning and again at night. You do not want to water them too often. Sustaining the right temperature, humidity, and light volume are of vital importance. The established light photoperiod will define your end product. You also want your hemp plants to have at least a little root system in the soil. Another thing you should be doing is using fertilizers and pest control products. You also want to wait for your hemp crops to be at least 3 feet tall to harvest them. This will allow you to harvest the seed as well. When your plants are growing, keep them well-watered and fertilized. Hemp growing is quite easy when you get used to it. You will need to do a bit of research, a bit of experiment, a bit of try-outs and fails. But eventually, you will for sure succeed.

Harvesting the Hemp Seeds from the Plants

Growing plants for seeds requires more time than growing plants for flowers, as the process itself is more time-consuming. You would like your seeds to be mature enough; it can be determined visually: premature seeds are of a light color with a sort of beige hue, while fully mature weed seeds are bigger, darker in color, with a dark brown hue or sometimes black stripes.

First of all, you harvest hemp and let them dry out for a week or two. This also helps seeds to reach their maximum maturity. The next step is to collect seeds, which can be performed manually or with the help of a special machine.

When harvesting hemp manually, you can simply rub the hemp flowers, and the seeds will easily fall out. Having sifted them and removed all the other unnecessary parts of the hemp plant, you will get your pure end-product. Brush them off, and they will be ready for storage.


Can You Grow More Than One Hemp Plant in a Pot?

It is not impossible, but there are a few things to keep in mind. First, the plants compete for nutrients, so you will need to fertilize them more frequently than if they were growing separately. Secondly, they may grow at different rates, so you will need to adjust their watering and feeding. Finally, if one of the plants is significantly taller, you may need to stake it so that it does not overshadow its smaller companion. 

Overall, it just requires a bit more work and consideration. It is pretty doable if there is enough space, soil, water, and light. Although once your plants are established and growing, transplanting them may be best.

How Long Does It Take Hemp to Grow from Seed?

Overall, indoor grow time for hemp plants can generally take around 90–120 days to grow from seeds to seedlings to mature plants. However, certain strains may have their own peculiarities, and, in addition, the growing period also depends on what you are growing it for: hemp fibers, flowers, or seeds.