When is the ideal time to apply fertilizer? We use it to improve the growth of our plants. And what kind of fertilizer do we use, and in what quantity? Everything you need to know about fertilizer use in your garden will be covered in a single page.
What Is Fertilizer?
In addition to having organic matter-rich soil (compost!), plants frequently require fertilizer applications to obtain the nutrients they require. Consider fertilizers to be dietary supplements. Tomatoes, for instance, require soil that is high in calcium.
These crops absorb nutrients from the soil, so if you have previously grown and harvested plants in your garden, you need replenish those nutrients in the spring before planting new plants. This is when organic or processed fertilizer comes into play. In order to maintain soil nutrient levels at a level suitable for healthy growth, fertilizers replenish lost nutrients.
Getting a basic soil test in the fall to determine the type and quantity of fertilizer to use to reach a “basic fertility” level is the best first step for novice gardeners. (See below for more information about testing.) Although we understand that not many gardeners have the time to conduct a soil test, we nonetheless advise it; you might even discover that your garden’s fertility level is sufficient.
However, use fertilizer sparingly: Accidentally overfertilizing a plant is the only thing worse than depriving it of nutrition. Only the nutrients that they require are used by plants. Excessive absorption may have negative effects or aberrant growth.
When to Apply Fertilizer to Your Yard
Before planting, fertilizer is typically placed into the garden soil and applied in the spring for edible crops. You can still carefully apply granular fertilizer—not liquid fertilizer, which can burn young roots—around your plants if you have already sowed your seeds or seedlings. The top three to five inches of soil will suffice; it is not necessary to work it deeply. The fertilizer should then be watered in.
Fertilize perennial flowering plants in the spring before they start to grow. A week or so before your final frost date, wait until the ground is no longer frozen. By doing this, the likelihood of the fertilizer’s delicate new growth being instantly destroyed by cold is reduced.
Although a spring application is generally a smart idea, keep in mind that plants actually require assistance during their peak growth.
For spring plantings of leafy greens like kale, arugula, and lettuce, this happens earlier.
In midsummer, squash and corn grow quickly. As a result, many gardeners plant long-season crops like corn with a tiny amount of fertilizer at the time of seeding and then add more in the early summer, right before the time when foliar growth is at its fastest.
Midway through the growing season, potatoes and tomatoes will require additional fertilizer as the plants absorb and utilize the nutrients already present. To promote more flowers and fruit than foliage, use a low-nitrogen fertilizer once tomatoes begin to produce blossoms.
The timing for perennial plants is determined by their growth cycle. For instance, June-bearing strawberries gain the most from fertilization after harvest, whereas blueberries benefit from fertilizer applied early in the season around bud break.
When dormancy ends, ornamental trees, shrubs, and perennials are frequently fertilized at the start of their growing season.
Do a Soil Test Every Time!
A “soil test” is the only accurate method to ascertain the amount of nutrients in your soil. You’ll have plenty of time to get the results if you test in the fall. In most cases, your local cooperative extension offers soil tests for free or at a minimal fee. This won’t have to be done annually. Understanding your soil, building it up, and then just applying fertilizer annually to maintain the soil’s fundamental fertility level are the objectives.
You might even discover that you have high nutrient levels if your garden has been fertilized for years. If your soil is already rich in nutrients, you should avoid adding more as this could potentially hinder the growth of your plants. Find out more about conducting a soil test.
What Type of Fertilizer and How Much Should I Use?
The label of a fertilizer bag will be a combination of numbers, such 3-4-4, 8-24-8, or 12-12-12. These three figures stand for the three most vital nutrients that plants require: potassium (K), phosphorus (P), and nitrogen (N). The figures represent each nutrient’s weight % in the bag. The percentage of the bag’s total weight can be calculated by adding the numbers; the remainder is merely filler to make application easier. Other nutrients, such as calcium, magnesium, iron, and manganese, might also be present.
Use a standard vegetable fertilizer to get your garden started. We use vegetable and herb plant foods with a 3-4-4 number for vegetables. To assist avoid blossom-end rot, we use a different fertilizer with a 3-4-6 ratios specifically for tomatoes. This fertilizer also contains calcium.
Because it is necessary for the growth and development of roots, phosphorus is significant. Potassium increases a plant’s resistance to disease. Take note that the first value, nitrogen, is lower. Have you ever seen tomato plants with luxuriant foliage but no fruit or flowers? This is because too much nitrogen promotes the growth of leaves.
The majority of nitrogen is needed by vegetable crops after they have reached a significant growth stage or have started to bear fruit. Excess nitrogen before this point slows down maturity and lowers yields and flowering. The decomposition of organic waste in your soil will also provide nitrogen to your plants.
Nitrogen side dressings (sprinkled in the center of rows) are beneficial for certain plants later in the growing season. The plant frequently need more nitrogen than the first two can provide, thus a nitrogen side dressing is required. However, that relies on the vegetable.
Three weeks after transplanting, broccoli, cauliflower, and cabbage can benefit from additional fertilizer.
Once flowering starts, peas, beans, cucumbers, and muskmelons can all benefit.
Tomatoes can be utilized more around two weeks after collecting your first tomato, and then again a month later. Peppers, eggplants, and tomatoes all benefit when the initial fruit sets.
One week after the tassels appear and when the plants are 8 to 10 inches tall, sweet corn can profit.
About a third of plants should be planted for turnip greens, mustard, kale, and spinach.
Sweet potatoes, watermelons, carrots, beets, turnips, parsnips, and lettuce are among the veggies that shouldn’t have additional nitrogen added.
The amount of fertilizer to use per 1,000 square feet of garden space should be shown on the fertilizer bag. If you need assistance transferring to your garden area, you can always ask the nursery personnel.
See our post on the NPK ratio and fertilizer basics for additional information.
Organic vs. Processed Fertilizers
Both organic and processed fertilizers are subject to the fertilizer requirements.
Natural elements like potassium chloride (KCl), sodium chloride (NaCl), and phosphate rock (P) are used to make processed fertilizers, often known as “synthetic” or “chemical” fertilizers. However, these natural ingredients are refined to increase their concentration. The majority of processed fertilizers, though not all of them, are water-soluble and quick-release, which can be helpful in particular circumstances since it allows nutrients to reach the plant more rapidly. (To slow the release, some processed fertilizers are coated.)
Plant-based compounds known as organic fertilizers release nutrients gradually as the soil’s microorganisms decompose. Most organic fertilizers are slow-release, meaning they contribute organic material to the soil so you don’t need to apply them as frequently. They are typically applied in granular form, or spread over the soil. (In addition, unlike many synthetic, water-soluble fertilizers that plants are unable to fully absorb, they do not leak into and contaminate rivers.) part organic fertilizers, such fish emulsion, biosolids, and animal dung, release part of their nutrients rapidly, but the majority are slow-release compounds.
The nutrients in organic and processed fertilizers are identical chemically. The ideal approach is to move slowly. Unlike fast-acting, synthetic, water-soluble fertilizers, which are essentially an overdose, slow-release granular fertilizers measure nutrients in a controlled, “digestible,” and safe manner.
Cost-wise, organic fertilizers are frequently still affordable for small gardens, even though they may initially cost more than processed fertilizers. Additionally, you don’t have to apply as frequently. The long-term advantages of organic soil surpass those of processed soil.
How Granular Fertilizers Are Applied?
Granular fertilizers should be applied by hand or with a spreader over a wide area for the season’s initial “starter” fertilizer application. Alternatively, if you have already planted, apply the fertilizer to your rows as a side dressing. To aid in the fertilizer’s leaching down toward the plant root zones, all dry fertilizers should be worked or moistened into the top 3 to 5 inches of soil using a hoe or shovel. In order to avoid damaging any roots, cultivate your plants gently if they are already developing.
Lighter supplemental treatments can be applied to the top inch of soil in perennial beds, crop rows, and around tree or shrub drip lines during the growing season. (To find out the recommended frequency of applications, see the label.)
Granular fertilizers can often be applied right before a good rain since this helps move the fertilizer into the soil where roots can get it.
How Liquid Fertilizers Are Applied?
When applying any water-soluble fertilizer, the chemical is first dissolved in irrigation water before being applied to the plant’s leaves and surrounding soil.
Caution: Avoid using liquid fertilizer right before planting! Some root hairs will break no matter how carefully you take plants out of their pots and put them in the ground. The fertilizer will get to the roots right away and penetrate them where they are broken, possibly “burning” them and resulting in more die-back.
Since the freshly laid plants should have healed from any root damage by then, many gardeners wait two to three weeks after planting before feeding with liquid solutions.
If the soil is dry, it’s crucial to fully water plants with plain water before using liquid fertilizer to prevent scorching the roots. Additionally, make sure the fertilizer is diluted according to the directions; otherwise, the leaves may burn. The fertilizer can be pumped through your irrigation system using an injector mechanism.
Applying liquid sprays in the early morning or early evening on dry days is ideal since the leaves will have more opportunity to absorb the substance. Steer clear of days that are too hot for foliage to burn.
Find Out More About Garden Fertilization
For additional fertilizer-related questions, please use the form below. We also recommend gardeners to contact their nation’s free cooperative extension office for local guidance.