BackThe most common mistakes when starting an outdoor cannabis grow
05.03.2025
Starting an outdoor cannabis grow is an exciting experience, but many rookie growers often make basic mistakes in their planning, which can affect the future health and yielding capacity of their plants. Most of these problems can be avoided with a bit of information, so let’s review the most common mistakes, along with some practical tips that will help you to emerge victorious when it comes to harvest time.
1. Choosing the wrong location for your grow
One of the most common mistakes is choosing a bad place to plant, either because it has little direct sunlight, it’s exposed to adverse elements, or it can be easily spotted by neighbours and intruders. The lack of sun will slow down the growth of cannabis, causing the plants to stretch (i.e., to develop long and thin stems as they look for the light), which significantly reduces the final production of buds. On the other hand, excessive exposure to the wind can break the branches and dry the substrate too quickly. Security is also a key factor, as a visible grow can lead to theft or to being reported to the police.
- Solution: Ideally, you should choose a south-facing location that gets at least 6 - 8 hours of direct sunlight per day. Look for a discreet and protected area, for example near a wall or hedge that serves as a windbreak but doesn’t cast excessive shade. Accessibility also counts: a place near a water source will facilitate irrigation, and a space where you can work comfortably will help you to look after your plants on a regular basis.
2. Using the wrong substrate
Saving on soil is one of the most serious mistakes that you could make. Many beginners turn to unprepared garden soil, or to cheap, low-quality substrates, which are usually too compact (or clayey), or contain latent pests. An example of this is homemade compost soil, which may include larvae that will force the roots to fight to grow and feed. In addition, a substrate that’s poor in organic matter may not provide the essential nutrients needed for growth.
- Solution: Invest in a good substrate for cannabis from the very beginning. This should be light and airy, with good drainage capacity and organic nutrient content; and with a loose structure that includes perlite, coco coir, or another aerating medium to ensure proper drainage. Adding worm castings or compost will help enrich the soil with beneficial microorganisms, which will in turn improve soil structure and fertility.
3. Not making the right decision between the ground or a pot
This decision is linked to the previous one and may be decisive. Planting in soil allows the roots to grow without restriction, resulting in larger plants. But, unlike with pots, the plants cannot be moved in the case of adverse weather conditions. Pots require more frequent watering because the substrate dries faster… And then of course there’s which size to choose.
- Solution: If the garden soil is suitable, planting directly in the ground can be highly beneficial. Prepare the area in advance: Dig and aerate the soil, mix organic soil amendments (worm castings, mature compost, guano) and drainage material (sand, perlite) as needed. If you need mobility or the soil is poor, opt for pots. Use small pots for seedlings (0.5 – 1 L) during the first few weeks, and then transplant them to larger pots as the plants grow: (5 - 10 L) for the vegetative period, and finally a large pot (15 - 20+ L) for the flowering phase.
4. Germinating outdoors
It often happens that rookie growers plant their seeds directly into the soil or definitive pot, leaving them out in the open immediately, without ensuring a proper temperature range or without protecting the seedlings from external factors. These include cold stress, strong winds, direct intense sun that can dehydrate them, or birds and insects that can eat them.
- Solution: The best practice is to start germination in a controlled environment. You can germinate at home and let the plants grow for one or two weeks under soft lighting (a fluorescent tube, a simple LED lamp, or close to a sunny window). When your seedlings are 1 - 2 weeks old, you can move them outdoors; but do this gradually: Take them out for only a couple of hours at first, protect them from strong winds, and don’t leave them totally out in the open from the very beginning. Gradually increase the time they spend outside and the intensity of sunlight that they receive.
5. Over or under-watering
Over-watering is perhaps the number one mistake that rookies make. Fearing that their plants are “lacking water", many growers water every day or keep the soil constantly moist, which can cause root suffocation and the development of fungi. On the contrary, too little watering can lead to wilted leaves and stunted growth. It is often said that over-watering is worse than under-watering, since a slightly dry plant can easily recover, but a plant with rotten roots is unlikely to survive.
- Solution: Do not water out of habit – water only when needed, checking the moisture of the substrate before each watering session, and adjusting the frequency according to the climate. Water only when the substrate is dry at a depth of about 3 - 5 cm. In summer, it may be necessary to water daily; but in colder or more humid climates, watering should be less frequent.
6. Inappropriate exposure to sunlight or incorrect photoperiod
Photo-dependent plants depend on the hours of light and darkness that they receive to flower properly. If placed outside too early, when the days are still short, they can start flowering prematurely and then revert to vegetative growth (or revegetate). This "flowering – revegetation - new flowering" process is highly stressful for the plant – it consumes too much energy and can lead to hermaphroditism, or simply to a loss in yield. On the other hand, exposure to artificial night lights can interrupt the photoperiod: a balcony light lit for several hours at night can prevent the plant from flowering as it should in the summer.
- Solution: In regions with short days at the beginning of spring, it is advisable to germinate indoors and wait until mid-season to take the plants outside, or until the days have more than 14 hours of natural light. If for some reason you need to start very early (i.e., in late winter), consider keeping the plants indoors with extra light until the length of the day increases, or opt for autoflowering strains.
7. Not selecting the strain according to climate and growing times
It is important to choose genetics adapted to the conditions of your environment, prioritising hardy strains if you live in humid areas. Accurately calculating the growing times is also crucial. If you sow too late, the plants will not have enough time to develop before flowering; whereas if you start too early, you could face problems such as frost or premature flowering.
- Solution: Do some research into the most suitable varieties for your area. Photo-dependent strains should be planted in mid-spring so that they can grow sufficiently before flowering. Autoflowers can be sown in several batches throughout the summer.
8. Other common errors to avoid
Furthermore, there are several other frequent mistakes that should be internalised to avoid falling into them:
- The grower should also be a meteorologist: Climate forecasting is always a plus. Anticipate the unexpected and use stakes or meshes to protect the branches from the wind; cover the plants with plastic or tarpaulins in case of heavy rains; and move the pots into the shade during extreme heat waves.
- Don’t move the plants around unnecessarily: A little controlled movement is fine (for example, rotating the pots so that the plants catch the sun more evenly). However, if you drastically change the plant environment too often, they can become stressed. Plants do appreciate a certain stability in their microclimate.
- You should keep a record and learn from past mistakes: Write down the time of germination, the time of fertilisation, and the times when problems emerged, and how you fixed them. Every mistake is a valuable lesson: Each grow will make you a better grower if you reflect on what happened.
- Don’t expect miracles without putting in the effort: Finally, a common mistake is to think that the plant will grow on its own without any care – a concept which usually ends badly. A successful grow involves dedicating some time to it every day or two, even if it’s just to keep an eye on it.
And please get this motto tattooed on your arm: Perseverance always trumps negligence. Growing cannabis outdoors is a continuous learning process, but with practice and attention to detail, each new season will be better than the last.