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Buyer's Guide

How To Master Cannabis Roots



Is your marijuana seedling growing bottom up? Does your taproot appear as if it is growing upwards? If this is the case, it is certainly not a good thing. The taproot is very fragile and exposure to light, and other elements, even for a short, could make it dry or get damaged irrevocably. 

If this happens to your plant, we have several remedies that we will explore in this article, so, let’s dive right in!

When should you do root surgery?

Plant surgery is one of the options you should consider strongly if your seedling is growing upside down. This might get your seedling to start growing in the right direction. 

To do this correctly, carry out the following steps:

  1. Get a new rapid rooter. Because your seed already has a root that is relatively long, cut open your plug lengthwise to allow you to place the seedling inside it gently in the right position. This helps you prevent “pushing down the seed”. 
  2. Use a pair of tweezers to extract the seed from its home of origin. Pick it up from the shell and avoid touching the root as it is very fragile. 
  3. Lay your seedling in the split-open rapid rooter, gently closing the plug around it. The plug should go into place easily with barely any sign that you had opened it. 
  4. Place it in the right position.

As your seedling was ready to sprout, and has now been placed in the correct growing position, it should be able to pop its head out in just 12-24 hours! Most times you will be able to see the leaves only, but occasionally you will see the seedling actually push its shell above the ground. 

The plant is then able to get rid of the shell and start growing!

When Should you not attempt surgery? 

If the young taproot appears above the soil but seems to be already finding its way to the right direction, surgery might not be necessary. However, if you are worried, you can cover the taproot, either with a little bit of soil, or with a piece off the edge of a rapid rooter, until it sprouts its leaves. 

Though your seedling may look weird at first, if left alone, it will more often than not correct itself and start looking normal after some point. After all, seedlings are inbuilt to take care of themselves! As long as the tip of the taproot remains moist, your seedling should be fine.

When is a protruding root actually a stem?

If the “root” that is peeping out is starting to look green like a stem, you need not worry at all. This green appearing root might be a stem that is still not strong enough to push the seed up. Given some time, the seedling should be able to overcome this hurdle and progress to the other stages of development. Actually in most cases, if you weren’t keenly watching you wouldn’t even know the plant had experienced any difficulties.


When seedlings are tiny, they are better off in small pots. Bigger ones contain high humidity amounts which might overwhelm the new plants, which might even end up dying. 

However, a time comes when your seedlings are not so tiny and they need to move to bigger pots.

How will you know when your seedlings are ready to be transplanted?

  • The roots will start to entangle, and get out of the pot.
  • The seedling will have developed 4 sets of leaves.
  • They are about to outgrow their current container.
  • In preparation for flowering.

If a seedling is not transplanted in time, it might become root-bound which happens when the roots no longer have enough room to expand. You can tell that your plant is root bound if it experiences:

  • Flimsy new growth
  • Stunted flower production
  • Stem discoloration (reddening)
  • Nutrient sensitivity
  • Nutrient deficiency
  • It may also appear under-watered. If your plant needs water more than once a day, it’s time to transplant it.

The process of transplanting though very necessary is fraught with risk. Transplant shock could be extremely detrimental to your plants growth and development, even deadly, sometimes. However, if executed properly, it leads to strong root development, and healthier flower production. 

How to care for my cannabis seedlings

Every grower should understand how to care for their marijuana seedlings because as we have mentioned, this is the most fragile stage of the whole plant cycle. We will look at a few things you can do:

Caring for marijuana seedlings

Now that you have put your seedlings in their soil, the actual challenge begins. As we have discussed, cannabis seedlings are awfully fragile, with their frail roots, and tiny set of cotyledons (the first set of little rectangular leaves). Even minor stressors are able to take your seedlings down in just a few hours. Understanding your seedlings, and their specific needs, better helps you grow strong, high yielding plants. 

Marijuana seedling care entails very precise needs that the grower should understand and adhere to. The lighting, temperature, and humidity should be right on point with what they require. Not adhering to the specific needs of your plants could prove unproductive, and even fatal. It is easier to regulate the conditions of seedlings grown in a propagator, as the perfect environment can be created. Below are ideal conditions for cannabis seedling care.

  • Temperature: In the daytime, the ideal temperature for your cannabis should be 20–25°C, while they should be kept roughly 4–5°C cooler at night. High temperatures both stress your seedlings, and stunt their growth. At this early stage, this stress could prove fatal. When your plants are experiencing heat stress, their leaves will dry up and curl at the edges. If the heat stress continues the plants may develop pale foliage, as well as purple or red stems. It could also result in weak, wilting leaves which have downward folding tips.

If on the other hand the temperatures are too low, a seedlings’ cells can get frozen. This will interfere with its ability to transport water, nutrients, and oxygen, leading to stunted growth or even eventual death if not dealt with. This will result in stunted growth and eventually death if not dealt with properly. Signs of low temperature in a propagator or grow room are slow growth, wilting foliage, and poor plant turgor.  

  • Humidity: When the roots of their seedlings are still young and developing, cannabis plants absorb moisture chiefly by osmosis carried out in their leaves. For this process to be optimized, humidity should be kept at 40-60%. If the levels of humidity in your grow room or propagator drop below 20%, your seedlings are likely to experience symptoms similar to those found in nutrient deficient plants. These symptoms are most recognizable by spotted or yellow leaves. Conversely, if the humidity levels go above 60%, your plants will have wet spots that may lead to foliage wilt or rot. The wet spots could also attract fungi, pests, and other pathogens.

When the seedlings get to the vegetative stage, relative humidity should then be kept at 50%.

  • Lights: Seedlings are very sensitive to light, and could end up burning under strong LED or HID bulbs. Just like adult marijuana plants, seedlings develop burnt, crinkled leaves if exposed to light stress. 

If seedlings do not get enough light on the other hand, they will get lanky, and topple over. 

Our recommendation to get best results are growing your seedlings in a 18/6 light cycle with blue spectrum CFL bulbs for the initial 10-14 days. Once they have developed healthy, true leaves, and at minimum 2-3 nodes, move them under stronger LED or HID lights for vegging. 

Growing marijuana seedlings outdoors

In cannabis seedling care, we have to consider the plants grown outdoors. If you are growing your seedlings outdoors, obviously you won’t have the liberty to tweak humidity and temperature by the shift of a dial. However, you can choose one of these 3 options to care for your seedlings: 

  1. You can keep your seedlings indoors, and put them under CFL lights for the first two weeks. This will protect them from the elements, and by the time you’re transplanting them, they will be sturdier.
  2. You could keep your seedlings outdoors in the day, and indoors at night. However in this scenario, ensure that the daytime temperatures are between 20–25°C consistently. 
  3. Finally, you can use a greenhouse, propagator, or polytunnel to permanently keep your plants outdoors as they will allow you to manipulate the temperature and humidity.  

Cannabis sprout care

 In the same way as roots, shoots have strong survival instincts. As roots reach down for nutrients, shoots reach up for light in a phenomenon known as phototropism. If you notice that your plants have exaggerated vertical growth, the most likely culprit is stress caused by inadequate light. 

When considering the best light for a cannabis grow room, keep in mind that a less potent, well placed lamp is more effective than a more powerful, poorly placed one. To maximize on the light getting to your shoots, use a reflector or grow tents that allow for more even light distribution. 

As we discussed earlier, temperature also affects the growth of cannabis seedlings. Inappropriate temperatures will cause them to become flimsy and leggy, which is an indication of both stress, and unease. 

If you notice that your “new born seedling” seems too fragile or weak to properly grow upwards, you can use a vertical support to assist them. Also, blowing a slight breeze on them will make the shoots stronger as they will be forced to focus their energy on reinforcement, rather than stretching. This will allow the plants to continue growing vigorously with less focus upwards. 

Stalking fungi 

Early plants are usually prone to many conditions that put them at risk. The most common infestations are caused by parasitic fungi related to Pythium, and Rhizoctonia. These fungi produce a commonly occurring plant disease called ‘Damping off', which causes small plants to wither, and eventually die.

These harmful organisms that love warm and wet environments, prevent the movement and absorption of nutrients. They are almost impossible to get rid of once they infest and it is best to prevent them in the first place. Monitoring your moisture levels and not overwatering your plants will go a long way in avoiding them. If the surface of your substrate is still damp, do not add more water until it dries out.

How about root growth stimulation?

It goes without saying that it is vitally important that plants are well rooted. Properly establishing your roots is the first step towards a successful grow. In the first two weeks, you should make the most effort to ensure that your roots are developed, and established enough to absorb all the nutrients your plant will need.  During the first two weeks, you'll have to make sure roots are developed enough to absorb all the nutrients cannabis plants need. This is why it is recommended that you do not use any chemicals on the young seedlings, as they could damage the fragile roots. Ecological systems are usually the preferred way to go. 

Though often left out, root growth stimulation happens to be a very vital process. If a plant has poorly developed roots, it will be unable to adequately absorb the nutrients it needs to thrive and produce a bumper harvest. A good way of stimulating your roots is pouring a root booster into your irrigation water in the first and second weeks of your seedlings life. 

Another way of ensuring that your roots grow strong is by boosting the production of auxins. Auxins are strong growth hormones which are produced by plants and are greatly beneficial to the growth of both roots, and stems. Increasing the auxins in your plant means that your roots will grow more quickly. 

Cereal crops such as bird seed, wheat or some legumes could help towards this goal. Simply soak them in water for 8 hours and voila! You will have your auxin boosting solution. 

How about fertilizing?

Until your plants get to the vegging phase, they grow perfectly without any added nutrients apart from what was originally in the substrate. If your substrate was nutrient rich such as earthworm humus or manure, do not fertilize until probably the 4th week. If it is not, you can start adding nitrogen, potassium, and phosphorus rich fertilizers immediately the 3rd week kicks in, up to the start of the pre-blooming stage. 


Noticing your marijuana seedlings growing upside down may not be as catastrophic as it may appear after all! Simply follow the steps we have outlined, give your seedlings the best care, and you will be on the fast track to a bumper harvest! 




Sebastian is a passionate advocate of CBD's therapeutic potential, dedicating himself to exploring its diverse benefits. As a seasoned writer, he eloquently shares his insights and personal experiences with CBD, aiming to educate readers about its transformative power. His life's mission is promoting holistic wellness, with CBD at the heart of his advocacy.