How and when to fertilizer Cannas
Cannas are bulbous plants that produce beautiful flowers, which can be of different colors such as yellow, red or bicolor. In addition to their beautiful flowers, they are characterized by having striking green, purple or reddish leaves, a difference that occurs depending on the variety. The origin of these plants is Central America, and currently they can be found in countries around the world. Although it does not need much care to develop properly, it is good to add some extra nutrients. That is why in this post we will discuss everything about the use of fertilizer for cannas, what type to use, when to apply and more.
Surely you have heard of this plant as canna or canna lily, sometimes this can be confusing, but you should know that it is the same plant. What’s more, canna or canna lilies have nothing to do with lilies, just some morphological similarities. Another name by which they may be called in some places is Indian shot., but it is much less common.

Table of Contents
1. How to care your canna lilies?
I think I’ve already mentioned that these plants are easy to grow. Even so, I do not want to miss the opportunity to list some of the basic care that you should take into account, I promise that I will be brief:
- Location: if you live in cold climates, it is best to find a place with a lot of sun to plant it. While in warm places it is preferable to look for a place with semi-shade.
- Soil: The best is a soil rich in nutrients and with good drainage capacity.
- Irrigation: it must be very abundant in the periods of development of the plant (spring-summer). It should decrease in autumn and winter.
- Pests and diseases: the most common diseases are those related to excess mold, which causes rot in buds, stem or rhizomes. As for pests, they are usually attacked with aphids, mealybugs, caterpillars, etc.
- Fertilization: of course, this point will go hand in hand with the richness of the soil. We will take care of developing it in the following sections.
2. Essential nutrients for your canna lily
Regardless of which plant it is, they all need to capture nutrients from the soil, in order to develop properly, flourish and bear fruit. For this reason, if we want our canna to produce the best and most abundant flowers, we must guarantee that it has the nutrients it needs.
Sometimes the soil may be able to provide all the necessary nutrients, but generally it is necessary to make an extra contribution through fertilizers on our cannas.
Sometimes the soil may be able to provide all the necessary nutrients, but generally it is necessary to make an extra contribution through fertilizers on our cannas. Among the most important nutrients for a plant like canna we can mention the following:
- Nitrogen: essential nutrient for the chlorophyll formation process.
- Potassium: improves the resistance of the plant against diseases, in addition to helping the growth of roots.
- Phosphorus: key during the flowering process. In plants such as canna lilies, it is good to make an extra contribution of phosphorus during flowering.
- Calcium: mineral very important for the general development of any plant.
- Iron: is part of chlorophyll, so it is important for its formation.
- Magnesium: helps the general resistance of the plant, in addition to being part of the chlorophyll formation process.
Although I have mentioned 6 nutrients and minerals, I can list several more. In any case, the most important are the first three, nitrogen, potassium and phosphorus, being essential when selecting a fertilizer.
2.1 What are NPK values?
If you have ever gone to buy fertilizers you will surely have noticed that there are three numbers separated by a dash on the packages. Those numbers are the NPK values. But do you know what they mean? If you do not know, I will clarify it easily and quickly.
NPK values are three numbers that indicate the concentration of nutrients (nitrogen, phosphorous, and potassium) within a fertilizer. More specifically, it is the percentage by weight of each nutrient with respect to the total weight of the fertilizer.
That said, and to make it clearer, let’s analyze the following case. Suppose you have a 10 kg package of 10-5-15 fertilizer at home. In this case, 1 kg of the total is nitrogen, 500 g is phosphorus, and 1.50 kg is potassium. The rest is completed with other nutrients less.
If you are reading this post, you will probably be interested in learning about fertilizing these other plants.
3. Best fertilizer for Cannas
We already talked a little about the nutrients necessary for a good growth of your cannas, but what are the fertilizers that contain these nutrients, and are better adapted for this plant. Let’s look at that now, dividing between organic fertilizers and commercial fertilizers.
Among the organic fertilizers that it is always good to have a hand for the growth of your canna lilies we can mention; compost, cow guano, fish emulsion, worm castings, among others. In general, these organic fertilizers have a high percentage of nitrogen, with this generally what we obtain are higher canna.
In general, these organic fertilizers have a high percentage of nitrogen, with this generally what we obtain are higher canna.
Whenever you use fertilizers that require a period of decomposition (ex: compost, guano) make sure that the decomposition has been carried out correctly. Applying these fresh fertilizers can cause a lot of problems for your plants.
Regarding the commercial fertilizers that can be used, we can recommend the following; a 10-10-10 balanced mix or a 5-10-5 mix. Both are good options. Depending on which one you are going to use, the dose will change, we will see that detail in the next section
4. Feeding Canna lilies
We already know which are the most recommended canna fertilizers, now we must learn how and when to use them. A fertilizer applied at the wrong time or in the wrong doses can bring more problems than solutions.
Always be careful, and remember that in fertilization less is more, it is better to apply with a lower dose than recommended than to exceed it. The problems that an overdose brings are difficult or impossible to solve and can kill your plants.
4.1 How to fertilize canna lily?
We already said that your canna lily likes soils with a good amount of organic matter. Therefore, it is good to replace the soil of the first 5 or 10 cm with a mixture of soil and some compost rich in organic matter. Here the most recommended is to use compost or guano. A 50/50 mix of soil and one of these organic fertilizers can work very well.
With the application of organic fertilizers it can be enough for a good development of this plant. But if what you want is to notice a jump in quality in flowering, with more abundant and larger flowers, you should use commercial fertilizers. Knowing exactly the proportions of nutrients that we apply means that we can control and take better advantage of these fertilizers, achieving much better results than with organic ones.
If what you want is to notice a jump in quality in flowering, with more abundant and larger flowers, you should use commercial fertilizers
Get the 10-10-10 or 5-10-5 granulated fertilizer mix, the doses go hand in hand with the amount of nitrogen. So if you go for the balanced mix, one pound per 100 square feet is enough. Whereas if you are applying the 5-10-5, you can apply up to two pounds per 100 square feet.
The application must be uniform on the ground, avoiding direct contact of the compost with leaves and with the stem (it can burn it). Once it is evenly spread over the soil, you must accompany the fertilization with abundant watering, this will help a faster dissolution of the nutrients.
4.2 When to fertilize cannas?
Fertilizer for cannas should be applied only in the development months of the plant. With this we will help the growth of the leaves and improve flowering. Keep in mind that we must let it rest in the cold months, when the plant is not growing.
The first days of spring should be the ones selected to start fertilizing your cannas, having to make applications every 30 days. The fertilization period can be extended or agreed depending on the characteristics of the climate where you live. But always keep in mind that you need to fertilize up to about six weeks before the first frosts.
5. Fertilizing and caring your canna lily (Video)
In case you have any questions about what has been analyzed so far, we have selected a video (from Grow with Me channel), in which you can review how a canna lily should be fertilized. I hope it is useful for you and you can understand in a more graphic way everything you have read in this post.
If you are reading this post, you will probably be interested in learning about fertilizing these other plants.