FARGO — A young homeowner was lamenting to the experienced gardener next door that her rhubarb wasn’t producing large, tasty stalks. “Have you tried manure on your rhubarb?” asked the old gardener. “No,” she replied. “We prefer sugar.”
Rhubarb isn’t the only plant that produces better with additional fertilizer. Proper nutrition is the basis for nearly all plant growth.
The following are tips for fertilizing the plants in yards, landscapes, gardens and flower beds.
- Plants need nutrition just as humans do, and the three elements required in greatest quantity by plants are nitrogen, phosphorous and potassium, which are the three primary numbers listed on every fertilizer label.
- For best results, soil testing of gardens and yards can provide a baseline to determine present level of fertility and recommend any additions needed. North Dakota State University and University of Minnesota both have soil testing labs. An online search of their labs will give information on how to collect samples and where to send.
- Lawns require fertilizers relatively high in nitrogen, which is the first number in an analysis like 30-5-5, to promote green, leafy growth. Fertilize lawns around Memorial Day and Labor Day.
- Trees, shrubs, perennial flowers, annual flowers, fruits and vegetables require a more well-balanced or “complete” fertilizer, such as the common 10-10-10, which provides nitrogen for green, healthy foliage and phosphorous and potassium for flowering, fruiting and root development.
- Fertilizer formulations include dry granular types and water-soluble types you mix with water. Both can produce good results.
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- Although many fertilizers are specially packaged for plants like roses, tomatoes or trees, an all-purpose fertilizer like granular 10-10-10 or the common national brand of water-soluble fertilizer 24-8-16 can be effective for all, eliminating the need for many individual types.
- Since plant roots don’t have teeth to chew granules, granulated fertilizer must dissolve into a liquid so roots can absorb the solution. Granular fertilizers are best incorporated into the soil and watered to activate.
- Organic fertilizers are derived from plant or animal sources. Manure, compost and other organics are usually lower in fertilizer analysis with nutrients released slower but are longer-lasting, plus most enrich soil tilth.
- Inorganic, or synthetic, fertilizers are derived from minerals, or manufactured products. They react faster than most organics and are usually higher in analysis, but dissipate quicker and they generally don’t improve soil tilth.
- Both organic material and inorganic fertilizer can be combined effectively, if desired.
- Vegetable gardens benefit from fertilizing in June to increase quantity and quality of produce.
- Annual flowers in containers or flower beds can be fertilized throughout the growing season to promote continued bloom.
- Geraniums are considered heavy feeders, and respond well to water-soluble fertilizer applied every two weeks for prolific bloom.
- June is a good month to fertilize perennial flowers, fruit, shrubs and young trees, with July 4 being the cutoff date. Fertilizing after July 4 stimulates growth that might not have sufficient time to toughen or “harden off” before winter, leading to dieback.
- Fertilizing perennial flowers in June promotes healthy growth and bloom both this year and next. Next year’s performance often depends on the nutrition perennials receive this year.
- Young trees can benefit from fertilizer, but older, established trees generally grow fine on their own.
- Fertilizers in spike form provide nutrition, but materials don’t move laterally a great distance, making spikes less effective than granular or water-soluble types.
- For vegetable gardens, fertilizer can be broadcast and tilled in before planting, or side-dressed in bands beside rows or in a circle around individual plants. Follow label directions, which for 10-10-10 is about 2 cups (1 pound) per 100 square feet or about a half cup per 10 running feet of row.
- For young trees, apply 1 cup of 10-10-10 for every inch of trunk diameter, measured 4.5 feet above ground level, and distribute evenly around the root zone inside and outside of the canopy’s dripline, not next to the trunk.
- For shrubs, spread 1 cup of 10-10-10 evenly around large established shrubs. Apply a half cup to small, young shrubs.
- For perennial flowers, rhubarb and asparagus, spread 1 cup of 10-10-10 per 100 square feet of bed, or band each plant with a fourth to a half cup. Cultivate in and water.
- For strawberries, apply about a half cup of 10-10-10 per 10 feet of row.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at donald.kinzler@ndsu.edu.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at donald.kinzler@ndsu.edu.
FAQs
Without fertilizers, nature struggles to replenish the nutrients in the soil. When crops are harvested, important nutrients are removed from the soil, because they follow the crop and end up at the dinner table. If the soil is not replenished with nutrients through fertilizing, crop yields will deteriorate over time.
How do fertilizers help in plant growth? ›
Fertilisers work by providing essential nutrients to developing flowers, trees and veg, as a kind of multi-vitamin or meal replacement for the plant world. Many fertilisers also improve the way the soil works by helping it to retain water better and allowing air to flow freely, which is good for roots.
Why does fertilizing plants make them grow faster? ›
Fertilizers provide crops with nutrients like potassium, phosphorus, and nitrogen, which allow crops to grow bigger, faster, and to produce more food. Nitrogen in particular is an essential nutrient for the growth of every organism on Earth. Nitrogen is all around us and makes up about 78% of the air you breathe.
Should I fertilize new plants? ›
One final thought: Feed only well-established plants; fertilizing seeds or tiny seedlings will cause fertilizer burn. Just remember, these guidelines on feeding are just that—guidelines.
What happens if you never fertilize plants? ›
Plants that don't receive fertilizer will grow but typically at a slower rate, even during the more active growing period. According to Hanco*ck, "Most houseplants will survive (note: survive, not thrive) without fertilizer, especially if you repot every year or two."
What plants should you not fertilize? ›
Perennials that require no fertilizer: Included are ornamental grasses, false indigo, ground covers, butterfly weed, bee balm, coneflowers, black-eyed Susans, sea holly, dianthus, asters and veronica. summer: Use a quick release food in summer, instead of a slow release food.
Do fertilizers help or hurt plants? ›
Too much fertilizer is not only a waste of money, but it can damage plants and harm the environment. With the right amount of nutrients, however, your garden can thrive and provide pounds of produce for harvest.
How often do you need to fertilize plants? ›
When they're more actively growing in the spring and summer, they benefit from a little liquid fertilizer mixed into their water about once a month. If you're not one to remember to do that, go for slow-release granules or a nutrient tab you can just push into the soil every few months or so.
What makes a good fertilizer? ›
Most fertilizers that are commonly used in agriculture contain the three basic plant nutrients: nitrogen, phosphorus, and potassium. Some fertilizers also contain certain "micronutrients," such as zinc and other metals, that are necessary for plant growth.
Is too much fertilizer a problem? ›
Excess fertilizer alters the soil by creating too high of a salt concentration, and this can hurt beneficial soil microorganisms. Over- fertilization can lead to sudden plant growth with an insufficient root system to supply adequate water and nutrients to the plant.
Compare Top Fertilizers
| Keyword | Quantity | Usage |
|---|
| Scotts Turf Builder Weed and Feed | 14.29-pound bag | Grass and kills dandelions and clovers |
| Burpee Bone Meal Fertilizer | Three-pound bag | Plants |
| Simple Lawn Solutions Lawn Energizer | 32-ounce spray container | Grass |
| Down To Earth Rose and Flower Fertilizer | Five-pound box | Plants |
2 more rowsTo avoid over-fertilizing, applying a fertilizer every two weeks is not recommended. Fertilizing as often as every two weeks will likely lead to problems such as lawn burn, excessive grass growth, as well as polluted water that can lead to toxic algae growth.
What fertilizer is good for all plants? ›
Most gardeners should use a complete fertilizer with twice as much phosphorus as nitrogen or potassium. An example would be 10-20-10 or 12-24-12. These fertilizers usually are easy to find. Some soils contain enough potassium for good plant growth and don't need more.
What happens if you fertilize plants too often? ›
Too much fertilizer can potentially cause a chemical burn on the roots of your plant. In severe cases, it can also cause the whole plant to wilt and die. This is something that you might see happen within a few days of fertilizing.
Can plants survive without fertilizer? ›
One of the greatest misconceptions about gardening is that you cannot grow healthy plants without using fertilizers or pesticides. However, nothing could be further from the truth. Plants do not require fertilizer to grow. Instead, they make their own food through a process known as photosynthesis.
What plants benefit from fertilizer? ›
Exactly how often you fertilize your plants depends on the types you are growing and the time of year. Some garden plants are heavy feeders (meaning they need more nutrients than others). These tend to be species that grow fast and bloom a lot, including most annuals, fruits, veggies, roses, and hydrangeas.
When Should fertilizer be applied to plants? ›
Generally speaking, the best time to fertilize landscape plants is around the time they begin to grow actively. The worst time to fertilize plants is at the end of their growing season. Trees, for example, begin to wake up and grow in early spring, and typically are fertilized once in February or March.
What does fertilizer do to the environment? ›
Some of these impacts include algae blooms causing the depletion of oxygen in surface waters, pathogens and nitrates in drinking water, and the emission of odors and gases into the air. Nutrients from manure and fertilizers enter lakes and streams through runoff and soil erosion.
