Humans and animals alike need a constant supply of nutrients to live, and so are plants too. If non-stationary living things like us have an array of available and comprehensible nutritional information, the same thing can’t be said about plants.
As technical as it seems, plant nutrition is key to growing plants and maintaining an acre of farms to a simple plot of garden. Hopefully, with this guide, you’ll pack up more confidence in dealing with plant nutritional problems and the overall care for your plants.
Basic plant processes in making their own food
To get a background on plant nutrition, let’s take a look at some of the most important processes on how plants make their own food. Warning! This might be reminiscent of your biology class but is too important to be omitted.
The primary process of food-making in plants is through “photosynthesis.” To kick start the process, the plants would need to absorb energy from the sun. That energy is used to convert carbon dioxide (absorbed from the air) and water to food.
The plants have specialized compartments called chloroplasts that are most abundant in leaves - this is where most of the important sections of the photosynthesis process happen. Inside the chloroplast is chlorophyll, a pigment that’s responsible for reflecting back the color “green” on our naked eyes.
The end product of photosynthesis or the food particles of plants is “glucose” a type of sugar that’s present in the leafy and most of the plant-based food that we eat. Plants also produce a by-product called “oxygen” as a result of photosynthesis. Oxygen is immensely viable to the plants’ existence and ours too. If plants use oxygen for energy making processes, oxygen is part of the human cells’ lifeblood.
For plants, glucose is a large molecule that has to be broken down into several pieces before it transforms as a plant’s energy source. To break down glucose, the plant has innate biological machinery called “respiration.” During respiration, glucose is broken down into ATP (adenosine triphosphate), a form of energy for the plants. Respiration can’t take place without the presence of oxygen and the release of water.
Energy is what the plants use for growing, maintaining internal processes, growing roots to find more nutrients in the soil, and so on.
You might have noticed some dew-like droplets of water in the tips of the leaves of your plants. This is not from the condensed vapor from the air (but can sometimes be the case, especially in the morning) but the result of the release of water during respiration.
Glucose is the plant’s main food molecule but to enhance a plant’s health and yield quality (such as fruits, flowers, etc.), they’ll need nutrients like humans would need vitamins and minerals.
Types of plants and the unique nutrition they need
In garden plants, there are two main categories: the vegetative or fruiting plants. Vegetative plants are cultivated for their leaves and foliage. Examples of vegetative plants are herbs, lettuce, greens you use for salads, and so on. Vegetative plants can be ornamental too like ivy or coleus.
Fruiting plants are grown for either or collectively of their fruits and flowers. Examples of fruiting plants are tomatoes, peppers, ornamental plants (petunias, freesias, daisies, etc.) and so on.
Because each type has different yields, they need different types of nutrients too. To make things easier, remember that vegetative plants would need nutrients that would help them increase leaf growth while fruiting plants would need nutrients that help them yield more fruits and flowers.
There is still an overlap when it comes to nutrition because both plant types need a good fertilizer for leaf growth since these leaves are where most of the photosynthesis happens. But the key to making sure the right amount of nutrients is provided for, you have to curate or fine-tune the nutrient feeding yourself since you have the opportunity to personally observe the plants.
Although phosphorus is the vital component of ATP, fruiting plants would need phosphorus more than vegetative plants for the transfer of energy for root development and flowering production. Without enough phosphorus, fruiting plants would find it difficult to produce blooms and fruit sets.
Vegetative plants would need plenty of nitrogen and potassium. These nutrients are essential to the numerous processes in the plants.
Phosphorus, nitrogen, potassium, and many more nutrients can overlap with both vegetative and fruiting plants. Some nutrients for a particular plant type is just highlighted more than another type because of the differences in yield.
How do you feed your plants with nutrients?
The loam soil, a kind of healthy medium where most plants are grown, has more nutrients than what you think. Plants’ roots will get most of the nutrients they need in the soil, but it will be up to you on how to maintain the plot and what fertilizers to add.
Prepare your soil
A nice start for feeding nutrient-rich fertilizer is to prepare the soil. The soil is where your fertilizer would be mixed in. Keeping them healthy and well-maintained will let your plants easily absorb the nutrients that you’ll introduce to them.
Here are some things you can do in maintaining your soil’s health:
- Test your soil’s pH level and nutrient levels (nitrogen, phosphorus and potassium) through a soil testing kit which you can buy in any reputable hardware and gardening stores.
If your soil’s pH level is too low or way above 7, the nutrients present in the soil can’t be absorbed by the roots. Too much nutrients can over-fertilize the plants, which isn’t good either.
- Till hard and compacted soil with a rototiller. You can also go with the unconventional way of tilling, such as introducing worms to the soil using the sheet mulching technique. The sheet mulching technique is building compost right on the surface of the soil.
Purchase a fertilizer
One of the easiest and best ways of introducing nutrients to your plants is the use of fertilizers. You have several options to choose from, but here’s a quick purchasing guide:
- Decide on whether you want a fast-acting or “slow-released” fertilizer. Either both options deliver the nutrients but with a slight difference when it comes to the rate of absorption.
A “slow-released” fertilizer takes longer to get absorbed so this option is best purchased when you don’t have an obvious problem for nutrient-deficiency. If you suspect a nutrient deficiency among your plants, use the fast-acting fertilizer.
- Know your NPK (Nitrogen, Phosphorous, and Potassium) ratio. Nitrogen, Phosphorous, and Potassium are some of the basic nutrients your vegetative or fruiting plants would need. It’s important that you know the correct ratio of each nutrient.
On a fertilizer bag or package, you’ll see that there are three numbers separated by hyphens. These numbers respectively indicate the ratio (or sometimes, percentage) of Nitrogen, Phosphorous, and Potassium contained in the bag.
Still confused? Let’s take a look at some examples: In a bag of 100 lb fertilizer that has an NPK nutrient value of 4-6-4, you’re getting a 100 lb fertilizer of 4 lb of nitrogen, 6 lb of phosphorous and 4 lb of potassium, the rest of the bag are fertilizer fillers.
- Decide on which NPK ratio combination you are going to purchase. The type of plants grown is going to dictate the best NPK ratio to purchase. Since fruiting plants need a higher amount of phosphorus, you’ll want a bag of fertilizer with a higher percentage of phosphorus.
In vegetative plants, you don’t need to be cautious on the ratio of phosphorus; you should focus instead on the ratio of nitrogen and potassium.
For example, you’re trying to grow grass, a type of vegetative plant. Since you already know that grass won’t need much phosphorus to grow, you won’t mind purchasing a fertilizer bag with a slightly low phosphorus ratio of this value: 8-2-4. Because nitrogen and some potassium are key in growing a healthy vegetative plant, a slightly high ratio of the NPK value is something of a concern.
- Should I be worried about the number of fillers dumped in the fertilizer bag?
No. As you’ve probably noticed, the NPK ratios only play around small numbers and do not really go beyond 50% or so. What’s the rest of the fertilizer made of?
The fillers in the fertilizer are called inactive ingredients. Some of the common inactive ingredients are sand, sawdust, limestone, and so on. These inactive ingredients cannot really interact chemically with NPKs. They are considered mediums that help hold the nutrients and dilute their concentrations in the planting soil.
- Decide between granular fertilizers and liquid-based fertilizers.
Dry or granular fertilizers come in the form of granules. Growers can customize the ratio and type of nutrients by blending granules. This technique helps them fine-tune their fertility program, improving production efficiency and even overall plant quality.
Liquid-based fertilizers or simply, liquid fertilizers are water-based types of fertilizer solutions. Liquid-based fertilizers can have the same nutrient content as granular fertilizers with the only obvious difference of application.
Liquid-based fertilizers have strong points such as easier absorption (leaves can absorb nutrients from liquid-based fertilizers too) but have some weaker points as well.
Foliar application or the liquid fertilizer application to the leaves is short-lived and not continuous for the rest of the season. For this reason, the foliar application can’t be considered the main way of plant absorption. Instead, it is used as a corrective method on times when growing plants need additional nutrition due to deficiencies.
Feed your plants with fertilizer
- Applying granular fertilizers
Apply the granular fertilizers by distributing them evenly in your plot or gardening area. You can either spread the fertilizer by hand (if your plot is small) or through a machine such as a spreader (if the growing area is large). The other style of distributing fertilizer is by “side-dressing” or spreading the fertilizer only alongside the rows of your growing plants or seeds.
Granular or dry fertilizers should be tilled down to 4 to 6 inches of topsoil either with a hoe or spade. Add a dash of water to help soften the soil and to let the dry fertilizers go deeper. It’s important to only do gentle tilling, especially in a stage where your plants are already developing their roots and stem.
- Applying liquid-based fertilizers
Water-soluble fertilizers are introduced to the plant via dissolving the product in water irrigation and application to the leaves and soil around the plant.
Before the application of the liquid-based fertilizer around a plant’s soil, you need to thoroughly dampen the ground with plain water. If the soil is too dry, the liquid-based fertilizer will burn the plant’s roots to death.
Try to also correctly dilute the liquid-based fertilizer solution by carefully reading through the instruction manual of the product.
If you have an elaborate watering system, you could mix the fertilizer solution through the system.
If you’re planting a newly-transferred plant, don’t apply a liquid-based fertilizer at the same time. Why? Upon removal or uprooting of the plant from a pot or from another growing area, some of its root hairs will break.
If you’ve accidentally applied a liquid-based fertilizer on a newly planted plant, you’re increasing the risk of “burning” the roots causing them to die eventually. To prevent this from happening, wait for 2 to 3 weeks after planting before applying a liquid-based fertilizer. By then, the damaged roots are fully recovered.
If your method of distribution is through liquid sprays, choose dry days as “application” days. Pick early mornings and early evenings as the best times of application. Avoid hot days, the leaves are at risk of burning, and some of the fertilizers would just evaporate.
Additional note: when to fertilize?
Plants need most of the additional nutrients during their rapid growing season. These times are during spring for most vegetative plants, midsummer for flowering plants like squash, and mid-season for tomatoes and potatoes. Ornamental plants are fertilized early on their initial growing season.