The selection ofFertilizers for your garden plantscan be a daunting process. Fertilizers differ in important ways, e.g. B. what they are made of, how high their mineral content is and whether they are organic or not. Some fertilizers promote leaf growth, others promote flower and fruit formation. In this article we explain which fertilizer you should use for your garden plants and when you should use it.
Why should you fertilize at all?
Plants need to be fertilized because most soils do not provide the nutrients needed for optimal growth. Even if you are lucky enough to start with good garden soil, as your plants grow they will absorb nutrients and make the soil less fertile. Rememberthe delicious tomatoesand the beautiful roses you grew last year? This required a lot of nutrients from the soil. When you fertilize your garden, you replenish lost nutrients and ensure plants have the conditions they need to thrive this year.
NPK fertilizer: What do the NPK numbers mean?
There are three essential macronutrients, nutrients that are needed in large quantities, that are most commonly mentioned in fertilizers. If you understand how each of these components affects plant growth and know your soil's deficiencies (through a soil test), choosing the right fertilizer can be easy. Most fertilizer packages have three numbers listed on them (e.g. 10-5-5). These numbers represent the percentage ofNitrogen (N), phosphorus (P) and potassium (K), always in the same order (also known as “NPK”). A fertilizer that contains all three macronutrients is called a “complete fertilizer,” and if all three nutrients are included in equal proportions (e.g., 20-20-20), it is considered “balanced.” The ratio of the individual macronutrients to one another determines the predominant reaction in a plant.
Nitrogen (N)promotes vegetative growth (leaves and plant shoots) and is an important component of the amino acids from which proteins are made. Nitrogen is also necessary for the formation of the pigment chlorophyll, which makes plants green and is essential for photosynthesis. Since nitrogen, unlike the other macronutrients, evaporates easily and flows out of the soil, it is the macronutrient that needs to be replenished most frequently.
Phosphor (P)promotes the growth of roots and flowers as well as fruits and/or seeds that follow flowering. Phosphorus is important for all plant processes that use energy, such as: B. photosynthesis, new cells/growth or water regulation.
Potassium (K)activates enzymes that initiate processes that improve a plant's ability to deal with stress. Plant stress is caused by transplanting, heat, cold, drought, diseases and pests, among other things. Potassium is also important for overall plant health.
Three additional nutrients that are important, but in much smaller amounts:
- calciumis needed by plants in the cell membranes, at the growth sites and to neutralize toxic substances. Calcium also improves soil structure and helps bind organic and inorganic particles together.
- Magnesiumis a component of chlorophyll. Without it, plants cannot process sunlight.
- sulfuris a component of many proteins.
Below are some examples of how you can use fertilizers to promote desired growth. These examples assume that the nutrients in your soil are “balanced” but deficient, or that you are using a container of potting soil that contains no nutrients.
For growing seedlings indoors
Have you grown your own seedlings? As soon as these two true leaves have developed, you can start fertilizing. At this stage it is best to give the plants aorganic, diluted, balanced liquid fertilizerto ensure that the plant as a whole is supplied with nutrients. Somecommercial fertilizers, especially non-organic ones, are quite strong and should be diluted by half or more to avoid burning the delicate plants. If you want to fertilize with every watering, dilute even more. Once the plants are larger and transplanted, you should start using more targeted fertilization.
Leafy vegetables and lawn in spring
Once seedlings like lettuce and kale look vigorous and have about 4 true leaves, you should give them oneFertilizer with higher nitrogen contentto promote healthy, leafy growth. The same goes for your lawn in the spring or, believe it or not, bulbs!
Fertilizer for flowering plants
Once flowering plants like tomatoes and zinnias are almost large enough to produce flowers and fruit, consider planting themFertilizer with a higher proportion of phosphorus (P)give. The larger the plant is before flowering, the more flowers, fruits and seeds it can produce. Larger plants also provide more shade for the fruit, which can be sensitive to sunburn.
Pflanzenstress
Plants are occasionally stressed, e.g. B. during a heat wave, when transplanting or due to pests and diseases.Potassium (K)can help plants cope with this stress by controlling their systems efficiently. For example, potassium helps regulate water so that the plant can respond appropriately to drought by storing water better. Transplanting also causes stress as the root ball is broken up and the plants are exposed to new environmental conditions (real sun, cool nights, new soil, etc.). Algae are excellent organic sources of potassium.
And what about the pH value?
Even if the right nutrients are present in the soil, some of them cannot be absorbed by plants if the soil pH is too high or too low. For most plants, soil pH should be between 6.0 and 7.0. You can measure the pH of your soil with a soil test. You can send a sample to a lab or purchase a home kit and do it yourself. The pH value can be increased with lime or wood ash. Sulfur or aluminum sulfate, on the other hand, can lower the pH value. Remember that it is best to slowly raise or lower the soil pH over the course of a year or two. Drastic adjustments can be worse. Here too, using compost is a helpful solution. Compost moderates soil pH and is one of the best ways to maintain the ideal pH of 6.5.
Liquid or dry fertilizer?
liquid fertilizerworks faster, but should be used more frequently (weekly to monthly) as it does not stay in the soil for very long. Plus, it has an almost immediate effect and is probably the best choice for seedlings grown indoors or for plants that have a visible deficiency. MostDry fertilizer (or granular fertilizer)are released slowly over one to several months, so you spend less time applying them. It is usually incorporated into the beds before planting. In most cases, plants can also be fertilized during the growing season by applying the fertilizer to the soil around the plant and incorporating it lightly with a hand cultivator. Dry fertilizer is an excellent way to provide your garden with all the macronutrients important for success. You can apply a more targeted dry fertilizer if necessary or use a targeted liquid fertilizer regularly. Always follow fertilizing instructions. Too much fertilizer can burn plants and cause irreversible damage and stress.
Organic or synthetic fertilizers?
Does it really matter to plants where they get their nutrients from? Yes, because organic and synthetic fertilizers deliver nutrients in different ways. Organic fertilizers are made from naturally occurring minerals and organic material such as bone or plant meal or composted manure. Synthetic fertilizers are produced by chemical processing of raw materials.
Generally, the nutrients in organic fertilizers are not water-soluble and are slowly released to plants over months or even years. For this reason will beOrganic fertilizers are best applied in autumnspread so that the nutrients are available in spring. These organic fertilizers stimulateuseful soil microorganismsand improve the structure of the soil. Soil microbes play an important role in converting organic fertilizers into soluble nutrients that can be absorbed by plants. In most cases, organic fertilizers and compost provide all the secondary and micronutrients your plants need.
Synthetic fertilizersare water-soluble and can be absorbed by the plant almost immediately. Applying too much synthetic fertilizer can “burn” foliage and damage your plants. Synthetic fertilizers give plants a quick boost, but do little to improve soil structure, stimulate soil life, or improve long-term soil fertility. Synthetic fertilizers have some advantages in early spring. Because they are water-soluble, they are available to plants even when the soil is still cold and the soil microbes are not yet active. For this reason, some organic fertilizers also contain small amounts of synthetic fertilizers to ensure nutrient availability.
For the long-term health of your garden, it's best to provide your plants with organic fertilizers and compost. This will result in soil rich in organic matter and beneficial bacteria.
Over-fertilization or under-fertilization can attract pests, cause pollution, increase costs, and lead to frustration and lost yields. Proper fertilization gives plants the nutrients they need to grow bigger, better and stronger!
