What is the Best and Fastest Way to Grow Cannabis Plants from Seeds

Although growing marijuana for personal use is not technically legal in Spain, there’s a tiny loophole that allows weed enthusiasts to grow up to 3 plants at home. Unless you are going to use your harvest for commercial purposes, it is okay to grow weed indoors.

[oxy-ou_classic_acrd ct_sign_sha256='52262fa9a1196a6626ceb7ebb3fa77fe16af891c78cd7938b62786dbf8db8a4b' ct_options='{"ct_id":65,"ct_parent":52,"selector":"-ou_classic_acrd-65-66","original":{"oxy-ou_classic_acrd_ouacrd_expand":"no","oxy-ou_classic_acrd_ouacrd_title":"Is growing weed legal in Spain?","width":"80","width-unit":"%","oxy-ou_classic_acrd_ouacrd_schema":"yes","margin-bottom":"50","oxy-ou_classic_acrd_-ou-accordion-label_typography_text-align":"center"},"media":{"phone-landscape":{"original":{"width":"100","width-unit":"%"}}},"activeselector":false}']

The answer, as usual, depends on the region. As of now, growing weed in Spain is illegal if it is going to be sold without a special license. Also, you cannot grow marijuana outside in plain sight. That means a balcony, a popular place to grow weed in Spain, is out of the question. Violation of this rule can lead to a fine.

However, there are no specific regulations related to growing marijuana indoors for personal use. The practice shows that 1-3 cannabis plants won’t cause any trouble if they are not located anywhere visible to the public.

So if you’ve always wanted to become a proud owner of top-notch homemade buds, here’s your complete beginners’ grow marijuana step by step guide.


What Items Do I Need?

Probably, you already have some required equipment but let’s make sure you have everything it takes to grow a big healthy cannabis plant.

To grow fast, cannabis needs:

  • Enough Lighting: to get the best bud quality, you have to provide your plant with enough light, either artificial or natural.
  • Soil or Hydroponics: growing marijuana hydroponically or using old-fashioned pot and soil? It’s better to decide on the medium beforehand.
  • Air: cannabis plants like well-ventilated spaces, so you might need to get your hands on a fan.
  • Temperature: cannabis plants die when exposed to high temperatures. Young plants thrive when the temps are around 20-30°C.
  • Good Quality Nutrients: you can buy a premade solution in a supermarket or make your own super-soil. Just remember: marijuana soil nutrients and marijuana hydroponic nutrients do differ. We will cover the difference a bit later.
  • Water: like any other living creature, marijuana needs water to survive and grow.

Do you miss one of those items? No problem. There are plenty of shops in Barcelona that offer everything you need to grow weed indoors.

[oxy-ou_classic_acrd ct_sign_sha256='e1271dcd6297024ea7d85b164f994cd3adb5e08895868eee9560ba19e68f32fd' ct_options='{"ct_id":78,"ct_parent":52,"selector":"-ou_classic_acrd-78-66","original":{"oxy-ou_classic_acrd_ouacrd_expand":"no","oxy-ou_classic_acrd_ouacrd_title":"How long does it take to grow marijuana?","width":"80","width-unit":"%","oxy-ou_classic_acrd_ouacrd_schema":"yes","margin-bottom":"50","oxy-ou_classic_acrd_-ou-accordion-label_typography_text-align":"center"},"media":{"phone-landscape":{"original":{"width":"100","width-unit":"%"}}},"activeselector":false}']

If you grow marijuana from seed, the process might take approximately 9 months. However, you can see the first results in just 9 weeks, if you choose any autoflowering strain.


What’s Better: Indoors or Outdoors Cannabis Cultivation?

Unfortunately, you can’t grow marijuana outdoors for recreational purposes in Spain without a special license. That is why indoor cultivation is your only option.

However, don’t get disappointed as indoor weed has a bunch of benefits:

Top-Notch Quality: when you grow marijuana at home, you control the plant’s environment. If the setup is correct, you can expect premium-quality buds.

Adaptability: you don’t need a backyard or a lot of space to grow weed from seeds. Even a square meter of your apartment will do.

Multiple yields: you are not dependent on the weather anymore. You can start another cycle right after you harvest.

Privacy: since you cannot officially grow cannabis at home in Spain, you may want to conceal your plants from the public.

[oxy-ouacfg_slider ct_sign_sha256='cc950b1815ba5453ee5a5f3c91d552909792a34e36e99dfce409c0da7ee7c128' ct_options='{"ct_id":60,"ct_parent":59,"selector":"-ouacfg_slider-60-6","original":{"oug_images":"69,70,71,72,73,74","oxy-ouacfg_slider_ouacfg_alttag":"no","oxy-ouacfg_slider_image_fit":"Cover","oxy-ouacfg_slider_ouacfg_sldtype":"carousel","oxy-ouacfg_slider_ouacfg_sldeffect":"slide","oxy-ouacfg_slider_columns":"3","oxy-ouacfg_slider_enable_lightbox":"yes","oxy-ouacfg_slider_ouacfg_sldh":"300","oxy-ouacfg_slider_image_size":"full"},"activeselector":false}'][/oxy-ouacfg_slider]

Step 1: Choose Space for Cannabis Cultivation

You can grow a cannabis plant almost anywhere; the choice is yours. Yet, you need to think about the sizes of your equipment.

To grow marijuana indoors, you will need the following:

Lighting: fluorescent light fixtures, induction, LED, or HID grow lights — you can choose from any of these options. The only difference is lighting efficiency and cost.

Air: don’t forget about air streams. To achieve them, you can use exhaust fans. You need to ensure that the temperature remains within a required range (20-30°C when lights are on and 15-20°C when they are off).

Step 2: Choose Your Medium. Hydroponic vs Soil Cannabis

You could either grow cannabis plants in soil or set up your own marijuana hydroponic system. Each medium has its pros and cons.

Let’s take a look at both options.


Soil is the most traditional and the most forgiving medium, which makes it a perfect choice for beginners. To get started, you can use any high-quality potting soil. The main rule is to stay away from artificial extended release fertilizers.

[oxy-ou_classic_acrd ct_sign_sha256='8eb358762f2d3212c8721d3aece4ecb1fd33f83528b9c22c815afe5d89cb2862' ct_options='{"ct_id":88,"ct_parent":82,"selector":"-ou_classic_acrd-88-66","original":{"oxy-ou_classic_acrd_ouacrd_expand":"no","oxy-ou_classic_acrd_ouacrd_title":"What is the best soil for indoor grow?","width":"80","width-unit":"%","oxy-ou_classic_acrd_ouacrd_schema":"yes","margin-bottom":"50","oxy-ou_classic_acrd_-ou-accordion-label_typography_text-align":"center"},"media":{"phone-landscape":{"original":{"width":"100","width-unit":"%"}}},"activeselector":false}']

If you are a first-time grower, start with pre-fertilized soil. This is the best soil for weed in case you don’t want to use any additional nutrients.

Or you could create your own marijuana soil mix rich in phosphorus, nitrogen, and other essential nutrients. Enrich the soil with some of these components: peat moss, manure, coco fiber, and/or guano.



This approach is absolutely soilless and more complex. Instead of getting all the nutrients from the soil, hydroponic cannabis uses concentrated mineral salt mixtures, which are consumed by the roots.

What are the benefits? It is the fastest way to grow big yields. What are the drawbacks? You will need to set up a complex system that includes rockwool, vermiculite, expanded clay pebbles, perlite, and more.

Step 3: Get the Right Container

The size of the container depends on your growing method and the size of your plants. You need a 40 liters pot to grow a large plant in case you’ve decided to stick to super-soil.

If you use a hydroponic system, you can grow little plants using smaller pots with clay pebbles.

Don’t forget to drill holes in the bottoms as marijuana is sensitive to overwatering.

Step 4: Choose a Strain

We’ve reached the best part: choosing a weed strain. If you’re a beginner, it is best to pick a quick-finishing autoflowering strain. Why?

The marijuana growing cycle consists of 2 phases: the vegetative stage and the flowering stage. Regular cannabis types require a shift in the light cycle to trigger flowering, and autoflowering strains do not need external cues to produce buds.

With autoflowering strains, you will get your first harvest in just 7-10 weeks.

Here’s a list of fastest autoflowers for your consideration:

  • Quick One: 13% THC content
  • Easy Bud: 12% THC content
  • Royal Cookies Auto: 18% THC Content

Step 5: Germinate the Seeds

The fastest way to germinate your seeds is to place them in a starter cube just like this one. The main rule is to keep the cubes moist and warm. If all the conditions are met, the seedling will crack open in just a few days.

Another method requires water and paper towels. Place seeds on moistened paper towels, fold them over, put them on a plate, and cover with another plate. The seeds will sprout in 4 days.

Step 6: Treat Your Cannabis Plants to Essential Nutrients

When your plant grows the first set of leaves, it means it is in the vegetative stage. It is time to bring in the required nutrients. To get nice buds, you need to give your plants the following macronutrients: nitrogen, phosphorus, and potassium. Do not forget about micronutrients: calcium, magnesium, iron, and copper.

You need this information if you are using regular soil. You can buy pre-formulated concentrated or powder form nutrient solutions. Just mix it with water and feed your plants at least once a week. Bear in mind that cannabis plants are easily burned, so don’t start at full strength.

If you are growing in any soilless medium, you will need to get nutrients specially made for hydroponics. For example, you could use the General Hydroponics Fertilizer Set.

Step 7: Water and Light

Cannabis plants can be very sensitive. That is why many growers prefer to check water pH levels and filter it. The required pH level should be between 200-300 PPM. To avoid fungal root diseases, do not overwater your plants.

As for light, cannabis plants require 18 light hours a day during the vegetative stage and 12 hours during the flowering phase.

Don’t Give Up

Growing weed from scratch is not an easy task. It takes a lot of expertise and knowledge. As you gain more experience, you will know how to tweak your setup to get the best results.

Get patient and enjoy the process!

© Cannabis social club Belveda 2021