All posts by Jordan Charbonneau

Common Nutrient Deficiencies in Plants

Spotting nutrient deficiencies in your plants can be challenging, especially if you’re new to gardening. Here are what a few common deficiencies look like and how to correct them.

Soil Nutrients

Nutrients in the soil can be divided into two categories macronutrients and micronutrients/trace minerals.

The first category, macronutrients, comprises primary nutrients nitrogen, phosphorus, and potassium and secondary nutrients sulfur, magnesium, and calcium. If you think your plant has a nutrient deficiency, these are the likely culprits.

The second category, known as micronutrients or trace minerals, includes boron, chlorine, copper, iron, manganese, molybdenum, and zinc. While these are still important to plant health, they’re needed in such small quantities that it’s less likely your plant is deficient in one of these micronutrients.

You can read more detailed descriptions of what all of these nutrients do in our post, Understanding Soil Tests.

Nitrogen Deficiency

A nitrogen-deficient plant will grow slowly and lack vigor. The leaves may turn pale and yellow before dropping off, with the oldest leaves dropping first.

Note that it’s easy to overdo it when adding nitrogen, especially if you’re using chemical fertilizer. Adding too much nitrogen will cause lush, dark green foliar growth at the expense of fruit and flower production.

There are many ways to add nitrogen to your soil. While you shouldn’t directly apply it to plants, animal manure is a good choice if you have access to it. Compost will also add some nitrogen, or you can add seaweed or kelp meal, fish emulsion, bone meal, coffee grounds, soybean meal, or cottonseed meal. Using legume cover crops also helps to increase your soil’s nitrogen levels.

Phosphorus Deficiency

A plant that is deficient in phosphorus will also lack vigor and may be stunted. It might drop fruit before it’s ripe or not produce fruit at all. The lower leaves may appear red or purple.

You can add phosphorus to your soil using rock phosphate, greensand, compost, or bonemeal.

Potassium Deficiency

Potassium deficiency will probably be most apparent in your plant’s leaves, which may be mottled or curled or have brown edges. The plants will also be weak and have stunted root growth. They will likely be more susceptible to disease and pest issues.

Good potassium sources include manure, compost, seaweed or kelp meal, potash, granite dust, greensand, and wood ashes.

Sulfur Deficiency

While sulfur is a macronutrient, a sulfur deficiency is much less common. Signs include stunted growth and pale, yellow leaves.

Add sulfur with gypsum, compost, or sulfur.

Magnesium Deficiency

If your plant is deficient in magnesium, you may notice poor flower and fruit production, stunted growth, and dropping leaves. Leaves may also appear mottled with yellow/white patches or purple/brown patches between the leaf veins.

To correct a magnesium deficiency, add limestone, manure, compost, or greensand.

Calcium Deficiency

Calcium deficient plants may die back or have buds that die. Their leaves will likely appear burnt, curling, or have necrotic leaf margins. You may also notice issues like blossom end rot and other signs of tissue necrosis.

Use oyster shells, eggshells, limestone, gypsum, or fishmeal to add calcium to your soil.

Notice how similar a lot of these symptoms are?

If you’re having problems with nutrient deficiencies, the best advice is always to get your soil tested. It isn’t complicated or expensive and will tell you precisely what you need.

It will also tell you what your soil’s pH is. Soil pH can affect plants’ nutrient uptake and may cause deficiencies even if your soil is otherwise fine.

If your soil test comes out fine, your plants may be struggling due to over or underwatering or disease issues.

How do I prevent deficiencies?

The first step you should take is to develop a garden rotation plan that includes cover crops. They’re excellent for preventing erosion and adding nutrients to your soil.

Yearly applications of good quality compost can provide a wide range of nutrients to your soil.

DIY Potting Mix

Like many aspects of gardening, potting soil, or potting mix is something you can DIY. Making your own can allow you to select and avoid certain ingredients, customize a blend for your specific plants, and potentially save money.

A potting mix or potting soil should be different than regular garden soil in a couple of crucial ways. First, it should be well-draining. This is key to prevent plants’ roots from being water-logged in potted situations. A potting mix should also be lightweight and consistent.


There are many ingredients available for potting mixes. What you select will depend on what you plan to use your potting mix for and your personal preference.

Sphagnum Peat Moss

Peat moss is the main ingredient in most potting soils. Though it doesn’t offer a lot of nutrients, it provides structure, is well-draining, and holds moisture well. Peat moss is on the acidic side, so it’s a good idea to use it in conjunction with limestone.

Unfortunately, peat moss may not be the most sustainable choice. It’s not like the moss that grows in your local woodlands. Peat moss forms over thousands of years from plant material (including moss) submerged in wetlands. As these wetlands take so long to regenerate, many consider peat to be a non-renewable resource.

Coir Fiber

Coir fiber or coco coir is sometimes used as an alternative to peat moss. It can often be found in compressed bricks and is made from the husks of coconuts in a process called defibring. Unfortunately, it can sometimes be pricey.

Rice Hulls

Essentially a waste product from processing rice, rice hulls are great for creating light, fluffy potting mixes. They help hold moisture too.


While some may disagree, compost may be the most important ingredient for many potting soil blends. In fact, a fluffy, well-aged, screened compost can be used for seed starting all by itself.


It may look a bit like styrofoam, but perlite is actually a natural, non-toxic ingredient. It’s a type of volcanic rock that expands when it is heated. It improves drainage and can hold and slowly release water.

Like peat, perlite may also have some sustainability issues. Perlite is typically strip-mined in the United States, China, Italy, and Greece.


Sand is good for creating well-draining potting mixes like those for succulents and cacti. You can use fine or coarse sands depending on what you’re growing.


Similar to perlite, vermiculite is a type of stone that’s a good addition for creating well-draining potting mixes. It also adds magnesium and calcium to the soil.

However, the mining and processing of vermiculite have some serious environmental impacts. Vermiculite is often found in combination with asbestos which is released during mining and processing.


There are a variety of fertilizers and amendments that can be used in potting soil. Kelp meal, bone meal, and slow-release chemical fertilizers are common choices.

These are more important if your plant is going to be in a container long-term. For example, you grow tomatoes in containers on your patio. If you’re just starting seeds, the fertility in compost should be more than enough.

Ground Bark or Composted Wood Chips

These ingredients are better suited for potting mixes used for larger plants rather than seedlings. They help hold moisture and aerate this soil. However, these can lock up nitrogen while they decompose so it’s ideal to add a bit of fertilizer like kelp meal if you’re using one of these.


Limestone is used to neutralize acidic potting mixes.

Creating Your Potting Mix

When selecting ingredients, you’ll want to consider what you’ll be growing. For starting seeds or propagating cuttings, you’ll want a mix that’s fine-textured, light, and fluffy. If you’re potting up larger annuals or perennials like fruit trees, it’s okay to use a coarser mix. For potting up dry climate plants like cacti and succulents, it’s a good idea to create a well-draining mix.

Here are a few sample recipes you can mix up at home. Feel free to play with ingredients. There are no correct or incorrect recipes, just what works best for you and your plants.

Seed Starting

There are two recipes you can use to start seeds. If you have a tendency to overwater you may want to use recipe two.

Recipe One:

  • Screened, well-aged compost
  • a bit of sand if desired

Recipe Two:

  • 1 part compost
  • 1 part peat moss or coir fiber
  • 1/2 part coarse sand
  • 1 TBS of limestone per gallon of peat moss (not required when using coir fiber)

Container Gardening

  • 1 part compost
  • 1 part peat moss or coir fiber
  • 1/2 part rice hulls or perlite
  • 1 TBS of limestone per gallon of peat moss (not required when using coir fiber)
  • 1/2 cup fertilizer (like kelp meal) per 6 gallons of compost

Larger Perennials & Trees

  • 1 part compost
  • 1 part peat moss or coir fiber
  • 1/2 part coarse sand
  • 1/2 part ground bark or composted wood chips
  • 1 TBS of limestone per gallon of peat moss (not required when using coir fiber)
  • 1 cup fertilizer (like kelp meal) per 6 gallons of compost

I’ve found that stirring these up in a wheelbarrow is one of the easiest ways to blend the ingredients and allows you to do big batches.

The Family Garden: How Much to Plant

For some gardeners, the ultimate goal is to grow as much of their own produce as possible. If that’s your goal, it can often be tough to plan a garden. How do you decide whether to plant three pepper plants or 20?

The go-to first advice is only to plant what you already eat.

The first step is to take a look at your grocery list or receipts. Look at how often you buy what. How many onions does your family purchase each week? How many cans of tomato sauce? With this information, you can then find out how many your family eats per year.

Unfortunately, even with this information, exactly how much to plant can be tough to nail down. You’ll be facing uncertainties in yields based on different varieties, weather, pest pressure, and much more. It may take a few years of experience before you achieve a plan that works for your family, which brings us to my next piece of advice.

Start a Garden Journal

Keep track of how much you plant this year and how it does! This information will make planning for next year a little easier.

Planting Recommendations

Here are a few planting recommendations for some common crops. These are just starting points! Feel free to alter these depending on your family’s needs. You may find they work perfectly, or you might have different numbers based on a wide range of factors.

Snap Beans

Planting anywhere from 10-50 plants per person is probably a good place to start. If you love beans or plan to freeze or can beans for winter, you’ll want to be on the higher end of this spectrum.


It may not seem like a lot, but 5-15 plants per person may be all you need. This will allow you several fresh meals during the summer with some to freeze.


Cucumbers are heavy producers, so you probably need fewer plants than you’d think. Planting 2-5 plants per person should be enough even if you want to preserve pickles.

Sweet Corn

Depending on if you want to can or freeze corn, you’ll probably want to plant between 20-100 row feet per person. Sweet corn is an excellent crop to succession plant to avoid getting your harvest all at once.


Unless you eat a lot of sauerkraut, cabbage may not be one of your family’s staples. It can, however, be an excellent crop for those looking to be more self-reliant. It’s easy to store fresh or ferment and can be grown during cool seasons. Plant 5-15 plants per person.

Check out the variety “January King” for a good winter cabbage.


Like cabbage, carrots can be an excellent storage crop. They also take up relatively little garden space. Try growing 30-60 plants per person. It’s also a good idea to succession plant carrots.

A great storage variety is “Oxheart.


If you like garlic, you may want to plant quite a bit. It stores well alone and is also great for flavoring other preservation recipes. 25-50 plants per person would be a good range to start in.


Many greens like chard, collards, and kale will continue to provide harvests for weeks. It’s probably safe to start with around 5-10 plants per person, which should give you plenty to dry, freeze, or ferment.


Lettuce grows fast but doesn’t keep long. Start with around 10 plants per person and plan on multiple successions throughout the cool seasons. You can also use shade cloth to help keep lettuce from bolting.


Unless you dislike onions, you’ll probably want to plant a lot. They take up little space. You may also use more of them than you’re accustomed to if you decide to add them to other preservation recipes like pickles or spaghetti sauce. Depending on your family, 50-100 onions per person should get you through a year.

Adding perennial onions to your garden can also help supplement this.


Peas are an easy, early crop that takes up relatively little space. Consider growing 20-100 plants per person, especially if you can freeze some.


Peppers are quite productive so you probably only need 3-5 plants per person. You’ll want to explore different varieties depending on your goals. Some are excellent for pickling, others are great for stuffing, while some make excellent hot sauce or paprika.

Squash & Pumpkins

Summer squash, winter squash, and pumpkins are generally very productive. Unless your family loves eating tons of squash, you probably only need 1-3 plants per person.


How many tomatoes you grow will largely depend on how much preservation you intend to do and what varieties you select. If you want to account for all your family’s produce, it’s probably a good idea to grow at least three varieties. Select a slicing tomato for fresh eating, a cherry tomato for snacking (especially if you have kids), and a paste tomato for preserving.

One Last Piece of Advice

Especially if you’re trying to produce as much of your own food as possible, plan to succession plant! This will help you keep fresh food on the table longer. Check out: