Outdoor in the Czech Republic: Is it better to grow autoflowering or photoperiod varieties?

The Czech Republic is neither California nor Spain. Outdoor growers here must reckon with a relatively short summer and the risk of an early end to the season. Anyone who plants an unsuitable variety outdoors in spring will be disappointed in autumn. Do you know which varieties are best for outdoor cultivation here?

Although the Czech Republic is not a large country in terms of area, it is geographically very diverse. We can find places with almost ideal conditions for outdoor cultivation, but also areas where the season is short and the summer is cold. A variety that ripens beautifully in sunny South Moravia may succumb to mould and cold weather in the foothills of the Krkonoše. That is why, when choosing seeds for outdoor cultivation, you should always be guided first and foremost by flowering time and the type of variety.

You may be interested in: Guide to shopping for the outdoor season

The difference between autoflower and photoperiod-dependent varieties

In seed banks’ range, you will find two main types of seeds – autoflower and photoperiodic. The difference lies in how plants react to changes in day and night length. Photoperiod-dependent varieties begin to flower outdoors only when the night length exceeds 10 hours, which in our latitudes happens during August. Flowering and ripening can then take 6 to 12 or even more weeks, depending on the variety.

Autoflowering varieties differ from photoperiods in that they flower independently of day and night length. Most autoflowers begin to flower roughly 3 to 5 weeks after seeds germinate. Autoflower cultivars have a shorter growing cycle than photoperiods grown outdoors. This is an advantage if you live in a place where the outdoor season is shorter.

Warm lowlands with a long summer

If you grow in the warmer parts of the Czech Republic, for example in South Moravia, the Elbe lowlands or the lowlands of South Bohemia, you have the best conditions for outdoor cultivation compared with the rest of the country. In lowland areas, you can often start planting outdoors as early as late April to early May and harvest only at the end of October or even at the beginning of November, if the weather is favourable.

In such conditions, it is a great idea to grow photoperiodic varieties. This is especially true if spring is warm and you can start planting early. Give the plants a long growth period before they begin to flower during August, and you will be rewarded with a larger harvest in autumn. More adventurous growers in lowlands can also try photoperiods with a flowering time of up to 10 weeks. However, this depends on the microclimate of the specific site. If your autumn is usually damp and it often rains, it is better to stick to cultivars with a flowering time of 8 to 9 weeks.

Of course, you do not have to avoid autoflower varieties in lowlands either, as their great advantage is a short growing cycle. Most of them can be harvested 60 to 90 days after germination. If you start planting early enough in spring, you may even manage more than one harvest per season.

You may be interested in: How to plant in spring: Choosing a site and preparing the soil

Areas at higher altitude

If you live in an area more than 500 metres above sea level, your outdoor season will be considerably shorter. In the Highlands, in northern Bohemia or in the foothills of the Beskydy and Jeseníky mountains, spring is colder and autumn arrives sooner. It is not unusual for plants to have to face morning fog and dew by the end of August.

In such a case, it is often safer to grow autoflowering varieties and plan their planting so that you make use of the warm weather in roughly the period from June to August. If you have the option, do not hesitate to plant the plants in a greenhouse or polytunnel. They will be protected from bad weather and will grow faster.

Of course, it is also possible to grow photoperiodic varieties at higher altitudes. However, it is better to choose those with a short flowering time of up to 8 weeks, or even better, “fast” (“early”) varieties, which flower faster than classic photoperiods. A great way to give plants a quick start at the beginning of the season is to pre-grow seedlings indoors and plant them outside once the weather is warm.

You may be interested in: How to pre-grow seedlings indoors                                                                           

Triploidy, F1 and other modern varieties

We must not forget that seed banks come up year after year with new varieties that are often bred using modern methods and aim to outperform classic hybrids in many respects. From the point of view of outdoor cultivation, stable F1 hybrids are particularly interesting for Czech growers. These are created by crossing two stabilised homozygous lines and show extreme vigour and resilience, which makes them ideal seeds for outdoor cultivation in the Czech Republic.

There is also increasing discussion of triploid varieties, which have three sets of chromosomes instead of the usual two. As a result, triploids are sterile and produce almost no seeds even when pollinated. According to several studies, polyploid varieties may grow faster and produce more secondary metabolites, but the research is still at a very early stage. In practice, the same applies to these varieties as to the others. Flowering time and response to changes in photoperiod are important.

You may be interested in: Grow three plants outdoors – Complete guide to outdoor cultivation

Czech outdoor growing is always a bit of a gamble with the weather, but by choosing the right genetics you reduce the risk that your plants will not finish properly, which can make the difference between an average and a great harvest. For more advice, guides and tips for beginner and advanced growers, follow the Higarden blog.