Why Do Plants Need Proteins? Best Protein Supplements For Your Garden

Plants need proteins for their healthy development, much like us. People who exercise usually take protein shakes as part of their diets to promote performance and enhance muscle recovery.

The plants can also enjoy a little protein shake every once in a while, but not literally! Please don’t give them your protein shake; their protein supplements are a bit different from ours!

Why do plants need proteins, and how can you make sure your garden is getting enough? This post will tell you everything about the protein requirements of your plants.

Why Do Plants Need Proteins In The First Place?

Proteins play critical roles in a variety of different processes that go on within plants. Here are some of the functions that rely on proteins:


Light dependant reactions of photosynthesis are catalyzed by four major protein complexes present in the thylakoid membrane.


Proteins help regulate the ability of the plants to adjust their orientation in response to the light source. It also helps mediate plants’ response to dark and light cycles, which is especially crucial for houseplants where the grower controls the light.

Don’t forget to read our posts about Houseplant Care & Tips if you want to learn more about your indoor plants’ specific requirements.

Intracellular Structure

Proteins are involved in building healthy cell walls for the plant that require adequate stress protection. Plants with weak cell structure can quickly go under stress due to temperature changes or pest infestations.

Pollen Production

Amino acids, especially lysine, play a critical role in pollen production for plants. An adequate supply of lysine will ensure that each flower bud produces lots of pollens to promote pollination.

Calcium Uptake

In the form of amino acids, proteins stimulate the opening of specific channels in the root cells that absorb calcium. Calcium is one of the building blocks for the plant’s cell walls. It also promotes the growth of root systems. An adequate supply of proteins will help absorb the calcium for a healthy plant structure.

But Where Does Protein Come From?

Now that you know why plants need proteins, you may be wondering where it comes from. Unlike most other nutrients, proteins aren’t directly available to the plants. It’s a long journey that begins at the roots.

The nitrogen in the soil isn’t of use to the plants. They rely on bacteria living around the roots and on root nodules to convert nitrogen into nitrates. Nitrates are absorbed by the plant roots and turned into 20 different amino acid varieties within the plant.

These amino acids get changed into proteins inside cell structures called ribosomes. The proteins formed inside the ribosomes are distributed throughout the plant and utilized to build new structures and metabolic processes.

Cutting it short, here’s what happens:

Nitrogen + Bacteria → Nitrates → Amino Acids In Ribosomes → Proteins

Proteins come from nitrogen in the soil. Nitrogen is one of the three primary nutrients that plants need for their growth. The three primary nutrients (nitrogen, phosphorus, potassium) are macronutrients because the plants need them in large quantities.

Common Symptoms Of Protein Deficiency

Since proteins are involved in a series of fundamental metabolic processes in plants and form the building blocks for new growth, its deficiency is easily noticeable. Stunted and slow growths are a typical protein deficiency symptom in plants from a nitrogen shortage in the soil. Other than that, you’ll find yellow-green leaves instead of the healthy dark green color. Older leaves also start shedding off faster than usual.

Suppose you see purple blotches on the stems and underside of leaves on tomato plants, for example. In that case, it’s a clear sign that the soil is short on nitrogen. This tells us that plants aren’t making enough proteins necessary for their healthy growth.

How To Decide If The Soil Needs Extra Nitrogen?

Once you’ve noticed one or more symptoms that link to protein deficiency, the next step will be to test your soil. Only once you have your soil tested can you know for sure if your soil needs extra nitrogen.

Always Perform A Soil Test Before Doing Anything
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You can either have your soil tested from your local extension office or check it yourself using a soil testing kit. Testing kits are readily available at plant nurseries. They will also tell you if your soil needs any other nutrients. Once you know your soil’s nitrogen content, you’ll see if you need to add any extra.

Fixing Protein Deficiency In Plants

As long as your soil is low on nitrogen, your plants won’t produce enough proteins for their growth. The only way to make sure they have enough proteins for growth is to replenish the soil with nitrogen. You can either go for organic sources or inorganic sources to correct the deficiency.

Organic Nitrogen Sources

While most organic sources do not offer an immediate fix, they allow a steady release of nitrogen to the roots over time, unlike chemical fertilizers. They’re safer since there isn’t much possibility of nitrogen toxicity with these animal and plant-based products. Here are some popular organic choices for adding more nitrogen to your lawn:

  1. Amending the soil with composted manure.
  2. Incorporating coffee grounds into the soil surface.
  3. Planting nitrogen-fixing species in your garden, such as pole beans and peas.

Inorganic Nitrogen Sources

Nitrogen is a significant component of most chemical fertilizers. When choosing synthetic fertilizers, look at the first digit in the NPK ratio. The first digit tells you the amount of nitrogen in the fertilizer and its concentration compared to phosphorus and potassium.

For example, a 30-0-4 fertilizer is a nitrogen-rich feed with 30% nitrogen, no phosphorus, 4% potassium, and other ingredients. Using a nitrogen-rich fertilizer such as this one will quickly boost the nitrogen levels in your soil.

But, it’s not a long-term fix since nitrogen supply enhanced in this way also gets depleted quickly. Adding manure or compost to the ground every year ensures that the soil is rich in nutrients at all times.

But, How Much Nitrogen Do Your Plants Need?

All plants need nitrogen to build their proteins and grow healthy. Specific requirements may differ from plant to plant. Some plants crave more nitrogen and can enjoy an occasional side-dressing of ammonium nitrate or urea. Side dressing means applying the fertilizer along the sides of the plant rows.

What Plants Love Nitrogen?

Tomatoes, sweet corn, okra, cucumbers, pole beans, and peppers are incredibly demanding nitrogen eaters. Leafy greens need more proteins than fruiting plants and will benefit from extra nitrogen throughout the growing season.

Nitrogen Requirements During Different Growth Stages

The nitrogen requirements of flowering and fruiting vegetation change as they grow. Most plants show a similar pattern once you know when your plants need nitrogen, and when only a little bit, you’ll learn how to fertilize them effectively.

The Vegetative Stage

Plants primarily need proteins for growing new structures. When the stems, leaves, and roots of the plant are still developing during the vegetative stage, they’ll need plenty of nitrogen to build new proteins. A high-nitrogen fertilizer is a good option if your soil doesn’t have enough.

The Flowering Stage

As the flowering stage approaches, plants transition from developing new leaves and stems to forming buds and fruits. This stage requires much less nitrogen than the vegetative stage.

Adding a nitrogen-rich fertilizer during this stage will practically destroy your harvest. Nitrogen will encourage plants to use their energy to make more leaves and stems rather than focusing on the fruits.

Nitrogen Toxicity

Be careful when adding extra nitrogen to the soil. Always add extra nutrients after having a soil test performed so you can know if, at all, any additions are needed and how much.

Symptoms Of Excess Nitrogen

While the plants will have plenty of nitrogen to make their proteins, their ability to absorb other nutrients might hinder, resulting in the deficiency of those nutrients.

That’s not all. With too much nitrogen, plants make proteins and focus on the growth of the green parts. You’ll see lush green parts with lots of leaves but little or no fruits and vegetables. Their flowering and fruiting ability will significantly reduce if they’re getting more nitrogen for making proteins that they would like.

How To Lower The Nitrogen Levels In The Soil

If the plants are exhibiting symptoms of nitrogen toxicity, stop giving them nitrogen right away. Adding mulch to the soil can lower the nitrogen levels as it tends to absorb the extra nitrogen. Growing nitrogen-loving plants like corn, broccoli, and squash in the ground with excess nitrogen can also lower it to the desired levels.

Final Words

After reading this post, you’ll have a better idea of why plants need proteins. Plants rely on proteins for their healthy growth, just like us. Without proteins, you won’t be seeing any lush green gardens with abundant plants. While they can make their proteins, they’ll need nitrogen to do so. Make sure they have enough of it, together with all the other nutrients, to sustain their growth.

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