The Three Stages Of Flower – Understanding the Flowering Cycle

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March 2, 2020

This article originally appeared in Garden Culture Magazine UK31 & US29.


Every stage of a plant’s growth demands a specific, balanced mix of nutrients and minerals. Flowering is busy; a period when plants direct all of their energy and resources away from overall growth and focus on producing the best flowers and fruits possible.

For Your Information

There are several different stages of plant development. The various lifecycle stages are as follows:

  • Germination (if growing from seed) 
  • Propagation 
  • Vegetation 
  • Flowering 

Each of the life stages divides into smaller individual phases, where plants perform many complex processes and have specific nutritional needs. By understanding the phases within each ‘main stage’ of the life cycle, you can work with them and tailor nutrition to push your plant to its maximum output.

The flowering stage can be broken down into three phases:

  • Early flower
  • Mid flower
  • Late flower/ripening 

By using the correct flowering additives at the right time, you can work with the plant’s natural growth rhythm to achieve phenomenal results. For this article, I’ll be using as an example a photoperiodism-sensitive, fruit-bearing plant with a 9-week flowering cycle.

Early flower – the transition phase (weeks 1-3)

Early flower occurs when plants cross over from vegetative growth to the production of flowers and fruits. When growing indoors, signal this period to your plants by changing the light cycle to 12/12 (lights on for 12 hours and lights off for 12 hours). 

A plant’s move from the vegetative stage into flowering will not happen overnight. The transition phase generally lasts for an average of two weeks, but depending on species, this can sometimes take up to three weeks. In growing terms, transitioning is referred to as ‘the stretch’. 

The plant shoots up in height, and flower sites begin to develop. General foliage growth will also continue as the plant takes time to re-program itself into full flower mode. Most feeding schedules for this phase will be similar to the last week of the vegetative stage, except for the introduction of a flowering additive.

A flowering additive perfect for use during this early transitional phase should adequately support the plant’s last burst of general growth. It should also supply the plant with additional nutrients, resulting in a boost in the number of potential flowering sites. 

Phosphorus helps boost the root system and potassium assists with flower and fruit formation. An early flowering additive works by increasing the production of metabolic triggers within the plant, which in turn, can increase the number of flowering sites from an average of 30-50% of the stem nodes to a whopping 70% or more! If you want more flowers, you need more flowering sites; using a flowering additive in this phase is essential to laying the foundations of a bumper yield. 

Mid flower- developing and gaining size (weeks 3-6)

Often in the third week of flower and certainly by the start of the fourth, the plants switch into full flower mode. Flower formations may still be small and relatively unformed at this point, but they should be present. From weeks four through six flowers or fruits develop rapidly, growing in size and weight daily. This productive stage signals a new era for the plants and along with it, a new set of nutritional needs. 

Plants need more phosphorus (P) and potassium (K) during flowering, especially during this phase. This is the time when increasing the dosage of the early flowering additive is a good idea, along with the addition of a PK 13/14 additive. PK13/14 acts like a chemical switch that tells the plant to cease all root, stem, and leaf growth and redirect all energy to growing flowers and fruits instead. 

Once fruit or flowers begin to develop, the plant’s need for phosphorus and potassium will significantly increase. Phosphorous is crucial to the plant’s metabolism, the transferring of energy, and the strengthening of the cell formation in flowers. Potassium helps transport water and nutrition around the plant, improving plant quality and strength. It also controls sugar production, which is essential for flower development and terpene production. 

The recommended time to apply a PK13/14 additive is three weeks before harvest, which can be anywhere between weeks four and six, depending on what you’re growing. Feeding schedules vary, but general guidelines recommend using it for anywhere between three and six days. Extended exposure to PK 13/14 can lead to an accumulation of nutrient salts in the medium, which in turn cause deficiencies by locking out other nutrients. 

Late flower – ripening and maturation (weeks 6-9)

Final stage of flower

This final phase of flowering is when the fruits of your labour ripen and mature, so they’re ready for harvest. At this point, fruit-bearing plants experience the most growth and gain the most weight. With the use of the correct flowering additives at the right ratios, bigger, heavier fruits with increased flavours will likely develop.

Sometimes referred to as a ‘ finisher’, a ripener/weight gainer supplies the plant with extra phosphorus and potassium. It also encourages the plant to use any nutrients it may have been storing. Ripener and weight gainers can also include small amounts of nitrogen, magnesium, and a complex mix of hormones and catalytic agents designed to enhance the weight, size, and production of oils in the fruits.

Potential Problems

Problems with using additives are common when administered at the incorrect developmental stage. Some growers cannot resist the temptation to increase the dosage levels of ripeners and weight gainers in a bid to push the plant to its maximum potential. It’s a gamble, and one that rarely pays off. Overfeeding can cause nutrient-lock, which stops a plant’s nutrient uptake and growth. Learning to read your plants comes with time and experience. 

The feeding schedule for nutrients and additives is a guide that should be followed as closely as possible. Every species and plant strain is different, and while some plants thrive at a higher dosage level than recommended, always approach such actions with caution. Increase dosage amounts slightly, by only 0.5ml at a time. There is a very fine line between unbelievable results and complete disaster. 

The flowering stage is more complicated than it would first appear. Working in sync with what nature intended is essential during this time. By understanding what a plant’s needs are in each phase, you can use flowering additives and ripeners to produce phenomenal results.

Rich Hamilton
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Rich Hamilton

Director at The Growers Guide
An industry veteran with over 20 years experience in a variety of roles, Rich is currently a business development manager for a large UK hydroponics distributor. The author of The Growers Guide series, Rich also writes on all aspects of indoor gardening, as well as being an independent industry consultant working closely with hydroponic businesses worldwide.
Rich Hamilton
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