NPK fertilizer for a butterfly garden

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NPK; What does it mean and why does it matter?
Which fertilizer should I choose for my butterfly garden plants?

Cloudless Sulphur butterfly drinks nectar from pink azalea flowers blooms

Cloudless Sulphur butterfly drinks from a pink azalea flower.
Prefers low pH - acid
Giant Swallowtail butterfly drinks nectar from a zinnia flower

Giant Swallotail butterfly drinks nectar from a zinnia flower.
Prefers high pH - alakine
Eastern Black Swallowtail butterfly lays an egg on parsley

An Eastern Black Swallowtail butterfly lays an egg on parsley.
Prefers low pH - acid
Luna moth caterpillar eats sweet gum leaves.

A Luna Moth caterpillar eats sweet gum leaves.
Prefers low pH - acid

Fertilizer bags, boxes, and bottles bear three NPK numbers that indicate the amount of Nitrogen N, Phosphorus P, and Potassium K. The percentage of each nutrient is displayed as 10-10-10 or 10-5-10 or another set of three numbers on fertilizer containers.

A gardener often ignores or is confused about these numbers. What does it matter? Which should a gardener choose? It's super simple and after reading this page, making the basic right choice will be easy.

Once the basics are understood, it's much simpler to make the choice of which fertilizers to purchase. Yes, that is plural, fertilizers. Most gardeners should purchase more than one type of fertilizer. Once fertilizers are purchased, choosing the right one from the gardening shed can make a difference between a beautiful green nectar plant loaded with flowers and a beautiful green nectar plant without many flowers.

Let's take a look at each of these three major nutrients needed for healthy butterfly garden plants.
Nitrogen: promotes green growth. The first number on the bag is the percentage of the bag that is nitrogen. To promote beautiful green growth in grass or non-flowering plants, a higher nitrogen number is the important factor in making a choice of fertilizer. Of course, using more fertilizer on a lawn results in faster growing greener lawns which will require more frequent mowing. Symptoms of nitrogen deficiency are yellowing of older leaves and red color / pigments along veins (that isn't the normal coloring of the plant).
Phosphorus: promotes flowering / blooming and fruit formation. The center number on the bag is the percentage of the bag that is phosphorus. It also promotes good root and seed development Remember seed formation follows fruit formation which follows flowering. For more flowers on your nectar plants, choose a fertilizer with a higher P potassium number. Fertilizers for tomato plants, african violet plants, and other specific fruit/flowering plants often have a higher P or phosphorus number. Symptoms of phosphorus deficiency are slower growth, slow maturing fruit and seed, darker green leaves, and an accumulation of red or purple pigmitation / color in the leaves.
Potassium: promotes growth of roots and stems and helps the plant breathe in carbon dioxide and release oxygen. The last number on the bag is the percentage of the bag that is potassium. A higher K or potassium number promotes overall health and root growth. Symptoms of potassium deficiency are mottled yellowing (that isn't the normal color of the plant), lower disease resistance, and overall poor health of the plant.

Basically, plants need nitrogen, phosphorus, and potassium. But different plants need different ratios of these nutrients.

A very few plants bloom best with very little fertilizer. Nasturtiums with high nitrogen will grow into beautiful green plants with very little bloom.

Soil pH:When one is choosing a fertilizer that is labeled for a specific type of plant, a gardener should be aware that other nutrients may alter the growth of the plant. Blueberries, parsley, sweet gum, and azaleas require a low pH very acidic soil, such as 4.5 to 5.5. Most plants prefer a pH of 6.0 to 7.0. Azalea, camillias, orchid, and blueberry fertilizers often lower the pH (acidity or alikanity) of the soil. Use of azalea fertilizer on many plants will result is sickly plants. Stocks, sweet peas, zinnias, snapdragons, violets, mums, clover, and asparagus do best with a higher pH.

Interstingly, bloom color of hydrangeas depend primarily upon the pH of the soil; low pH for blue blooms and high pH for pink blooms.

An added factor is that nutrients such as N, P, and K can be absorbed by the plant best between the pH of 5.5 - 7.5. Below 5.0 very little N, P, or K can be absorbed. If a gardener needs to change the soil pH, lime is added to make the soil more alkiline (higher pH) and sulphur or compost is often added to lower the pH of soil.

Plants require many elements, divided into groups such as macroelements, microelements, and other elements. Each has a specific role in a plants growth. The three basics are NPK; the three elements discussed above.