Many growers make one fundamental mistake when choosing cannabis seeds for outdoor cultivation – they select a variety because of its well-known name and do not consider whether it is suitable for growing in our climate. Usually, the harvest then does not have time to ripen before the first frosts, or they do not get a harvest at all because the plants fall victim to pests and mould.
What is the best cannabis variety for outdoor growing? It is not possible to choose just one – there are many cultivars suitable for the Czech climate. The ideal cannabis variety for a Czech grower must flower relatively quickly so that the plants have time to ripen before autumn arrives. Outdoor plants are more exposed to pests and mould. Some exotic varieties may struggle greatly in such conditions. Cannabis cultivars adapted for outdoor growing are acclimatised to weather fluctuations and resistant to insects and pathogens.
- Short flowering time
- Resistance to mould and pests
- Resistance to poor and changeable weather
Photoperiod varieties
Cannabis flowering depends on the photoperiod, that is, the length of day and night. Most photoperiod cannabis plants begin to flower when they have at least 10 to 11 hours of uninterrupted darkness. In our latitudes, this occurs in the first half of August. Plants grown outdoors therefore have only a short window in which to ripen. The first frosts here usually arrive already at the end of October or the beginning of November.
Seeds of cannabis varieties for outdoor growing
For outdoor growing in our conditions, we recommend choosing cultivars with a flowering time of 7 to 8 weeks. Pure or dominant indicas do very well here, as they can withstand cooler weather. If you are growing in a greenhouse, you can also choose from sativa and indica hybrid seeds, but it is better to select those with a predominance of indica genes. When choosing seeds for outdoor growing in our conditions, on the other hand, avoid pure sativas, which would have no chance of ripening here.
Autoflower varieties
Autoflower cultivars are the exception that proves the rule about cannabis photoperiodism – they flower independently of the length of day and night, several weeks after the seeds germinate. The growing cycle of autoflowers is therefore noticeably faster than that of plants dependent on the photoperiod. From seed germination to harvest, 70 to 90 days usually pass. Some growers take advantage of this and time the planting of autoflowering plants slightly later than photoperiod plants in order to provide the plants with the best possible conditions.
Seeds of autoflower cannabis varieties
The best autoflower varieties for outdoor growing are those that can withstand changeable weather. As with photoperiod plants, when choosing autoflower seeds for outdoor growing, it is better to select those with a short flowering time. However, thanks to the short vegetative period of autoflowers, it is possible to grow autoflower cultivars with a flowering time of around 10 weeks here as well.
When growing autoflower cannabis, it is necessary to ensure that the first weeks of the plants’ lives go as well as possible. Any slowdown in growth during this period will affect their size and yield. If you decide to grow autoflowers, wait for suitable weather before germinating and planting them out.
Fast varieties
Fast-flowering cannabis varieties, referred to as “fast” or “early”, have been bred to flower and ripen slightly faster than is usual for photoperiod plants. This unique type of cultivar is created by crossing a photoperiod plant with a ruderalis (autoflower) line. The result is plants that flower in response to longer nights but at the same time ripen very quickly.
Seeds of fast cannabis varieties
Growing fast varieties in the Czech climate is easy, and these varieties can be recommended to beginners. All you need to do is plant them at the beginning of spring like classic photoperiod plants, and nature will take care of the rest. Fast cultivars will ripen before the first frosts arrive. However, you do not need to worry that they will not grow before flowering begins, as with autoflowers, because they start flowering only at the beginning of August.
For more useful tips, advice and information for cannabis growers, visit the HiSeeds blog.