Grow Three Plants Outdoors: Part 7: We Start Flowering

Mid-August is a moment that many growers look forward to all summer. After months of growth, the first flowers begin to appear on the plants. In today’s instalment of the series, we will describe the correct way to fertilise at the beginning of flowering, explain why it is a good idea to support the plants, and discuss how to check the garden for hermaphrodites.

In the previous instalment, we described the first signs of flowering, briefly discussed shaping the plants at the end of the vegetative phase and selected a flowering fertiliser suited to your growing style. In the second half of August, signs of flowering should be visible on your plants. This is the time to take several steps that can significantly improve the quality of your harvest.

Fertilisation and nutritional supplements for the flowering period

As flowering begins, the plants’ nutritional requirements change. Their consumption of nitrogen (N) decreases, while their need for phosphorus (P) and potassium (K) increases. If you use a multi-component nutrition programme, you should now be fertilising with a flowering fertiliser. If you grow organically, you can provide the plants with nutrients using vermicompost or high-quality compost.

Many growers use PK boosters during flowering. The increased supply of phosphorus and potassium stimulates the plants and provides them with nutrients for better flower development. Use PK boosters from the 3rd or 4th week of flowering for a period of 2 to 4 weeks. As with fertilisers, if you use organic fertilisers, you should not combine them with synthetic inputs. A good organic alternative to PK boosters is compost teas, which also support microbial life in the soil.

An underrated nutritional supplement is silicon, which helps plants build stronger tissues and withstand high temperatures and drought more effectively. When growing in beds, silicon is unnecessary because the soil contains enough of it, but it can be useful when growing in pots, particularly if you use a coco substrate. In open soil, natural seaweed-based additives or bat guano are beneficial; the latter is also an excellent source of nutrients.

You may also be interested in: Why products based on silicon and beneficial microorganisms should not be combined

Supporting plants and protecting them from the weather

The first flowers may look inconspicuous, but within a few weeks they will become many times larger and heavier. Stems weighed down by flower clusters may bend or even break without support, which is a common problem with large outdoor plants. There are countless ways to secure plants against the wind, and much depends on their size. For smaller and medium-sized plants, support stakes will be sufficient. At the beginning of flowering, it is advisable to tie larger plants to a net or secure them from above using a retractable yo-yo support.

If you use protective sprays, stop as soon as the plants begin to flower. The exception is certain specialised sprays that can also be used during flowering. Pesticides and other chemical sprays must never be applied to flowers! If you are concerned that the plants may be attacked by mould, you can help them by thinning out some leaves to improve air circulation through the crop. However, be careful and never remove too many leaves at once.

Watch out for male plants and hermaphrodites

Although most growers now use feminised seeds, it is still worth checking the plants carefully for the presence of male flowers. At the beginning of flowering, some plants may show hermaphroditic traits. Remove such plants from the garden immediately. There is no point trying to pick out the female flowers. The pollen would ruin your entire harvest. If you grow from regular seeds, remember that male plants flower slightly earlier than female plants.

Check the plants every day. Carefully inspect not only the tips, but also the nodes, where flowers also develop. Regular checks take only a few minutes and can determine whether you harvest a quality crop or a pile of seeds.

That is all for today. In the next instalment of the Grow Three Plants Outdoors series, we will look at the peak of flowering and explain how to protect plants from rain and mould, which can threaten the approaching harvest.