LEDGrowlights101 is reader-supported. If you buy via links on our site, we may earn an affiliate commission at no extra cost to you.

How to Grow Cannabis Hydroponically (Without Soil)

Last Updated on

Growing marijuana hydroponically or without soil is a method that’s becoming popular these days. Follow the steps below and reap the results! If you want a more in-depth guide, we highly recommend the Marijuana Grow Bible.

1. Prepare the Materials You Need

You’ll need the following:

  • Seeds or clones
  • White paint
  • Hydroponic nutrients
  • Pots or containers
  • Coco coir or another medium for pots
  • pH detection
  • timer
  • lighting system

2. Prep Your Walls to Obtain Greater Yield

Your plants deserve the right amount of light even if they’re indoors and that is why you’ll need to paint your walls with semi-gloss white paint. Mylar can also be used because they can reflect light properly. But be careful, because mylar can be very efficient in reflecting light and heat; too effective that it can burn your plants.

Two_hydroponic_cannabis_plants

Credit: Plantlady223, Wikimedia Commons

3. Set up Your Lighting System

Position them where you deem fit. Remember to hang the lights properly because the light is vital for the growth of plants. In fact, an average crop needs about 3,000 lumens per square foot. And for a greater produce, a plant requires 7,000 to 10,000 lumens per square foot. You should then measure how much light your lighting system can provide to a plant after installing it.

Your lights shouldn’t be the cause of overheat which can ultimately burn your plants. To make sure the cannabis won’t be on fire, you should bear in mind that the maximum temperature shouldn’t go higher than 90° Fahrenheit.

VIPARSPECTRA UL Certified 600W LED Grow Light,with...
  • UL CertifiedLighting SAFETY is just as important as EFFICIENCY. The V600 as...
  • Optimal Spectrum& VEG & BLOOM SwitchesThe secret to VIPARSPECTRAs success...

4. Check the Ventilation

Proper ventilation is also needed for the cultivation of your crop. This is why you have to ensure that the growing area is ventilated the right way. If you’re not into cloning, then you should have seeds. And seeds need to germinate before the planting process. Be sure to germinate the best seeds only.

800px-Flowering_Cannabis_Plants

Credit: Cannabis Training University

5. Transfer the Seeds to Rock Wool Blocks for the Initial Growth of Your Plant

6. Feed Your Plants

Like any other crop, you need to feed cannabis with water and other essential nutrients in your hydroponic system. For the initial stage, the pH level of water should be 5.0 to 6.0. Remember that overfeeding your plants with additional nutrients is a no-no. Doing so will spoil them. Just give them the right amount of nutrients they need, then add more gradually.

General Hydroponics Flora Grow, Bloom, Micro Combo...
  • GH Flora Series is the original Building Block Nutrient System imitated but...
  • Users can adjust mixtures to suit specific plant needs; Enhances flavor,...

7. Check the Environment

Examine the pH level of the water you’re growing your cannabis crop with. It’s also crucial to check the nutrients and the lighting. Give your plants the appropriate amount of light only; otherwise, problems will occur. Also, inspect the ventilation. The environmental conditions of the plant should be faultless so that the vegetation and flowering will be perfect as well.

8. Examine the Height

During the vegetative phase, the height of the marijuana plant may be doubled. In a perfect world, the plant must be left in a vegetative stage until its height is 6” to 18”. If it has reached 18”, it’s a sign to begin flowering. Again, proper lighting is the key here. The plants should receive light 12 hours every day, which is why you’ll need a timer for the light schedule. You’ll then know the sex of the plant soon after. Female plants will begin growing white hairs while male ones will start growing tiny balls that appear like grapes.

marijuana-3065611_1280

Credit: Wild0ne, Needpix

9. Remove the Male Plants

You have to get rid of them since they will pollinate the female ones. In case you didn’t know, pollinate plants won’t ever develop that powerful taste the non-pollinated ones will.

10. Wait for It to Mature

This will test your patience, but hey, you have to finish what you started! Waiting for them to mature depends on the system you’ve set up. It takes approximately six to 12 weeks for the plant to become a mature cannabis sativa. You’ll know they’re mature when 50-75% of the pistils have become brown. And once they’re mature, that means they’re ready for harvest.

Tip: You should feed them only with water one week before harvesting; or else you’ll be able to taste the other nutrients when you smoke marijuana.

Don’t know the difference between hydroponics-grown and soil-grown cannabis? Watch this video below.