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Quick Tips When Choosing Vegetable Garden Fertilizer

by Frances Santos

vegetable garden fertilizerChoosing the right vegetable garden fertilizer can be confusing because there are a lot of fertilizer options in the market today. You might have heard that understanding your soil is the key to abundant produce. So how do you do it?

While some gardeners can easily say that their soil is acidic due to the excessive growth of certain weeds, others simply do not have any idea why they couldn’t grow a crop of any kind.

Does your soil need to be adjusted due to low potassium content? Is it acidic? What fertilizer blend is best to lower soil nitrogen content?

There is no need for a guessing game, perform a soil test. It will clearly determine the soil’s capability to provide nutrients and specify any nutrient deficiencies—whether the soil is undersupplied with potassium, phosphorous, calcium or magnesium.

Soil test results also supply accurate data regarding your soil chemical conditions, content of organic matter present in the soil, and information about the recommended type and rate of compost or fertilizer needed.

How To Test Soil pH

To measure the acidity or alkalinity of the soil, your local cooperative extension service or garden center can examine it for you. Collect a soil sample, send it to them, and wait for results. Soil testing kits are also available in garden centers for $30.

Soil pH

The ideal pH range for a vegetable garden is 6.5 to 7.0 because this range provides optimum soil nutrients for plants. Acidic soils have low soil pH and it can be adjusted by adding limestone to “sweeten” the soil. Limestone has magnesium and calcium which are both imperative to grow healthy plants. On the other hand, high soil pH means the soil is alkaline and therefore sulfur is added to correct it.

All-Purpose Fertilizer Blends

5-10-10 and 8-12-6 are some of the ideal all-purpose fertilizer blends. Generally, you can use any of these blends at sowing time about three to four weeks throughout the growing season. In case the soil test specifies a major nutrient deficiency, you can add products in the spring and autumn to adjust the soil and correct its balance. A frequent recommendation for vegetables is to apply a pound of 10-10-10 fertilizer or 2 pounds of 5-10-5 or 5-10-10 fertilizer for every 100 feet of row.

Significance Of N-P-K

As required by law, every fertilizer container lists the percentage by weight nitrogen, phosphorous, and potassium (N-P-K) analysis the product contains. Nitrogen promotes growth of stems and foliage. All-leaf produce such as cabbages and lettuce will benefit from fertilizers with high nitrogen content to have best-tasting leaves. Phosphorous aids healthy root systems. It is useful for plants from cucumber family, peppers and tomatoes. Potassium promotes fruit formation and flowering. It also gives the plants vigor, hardiness and ability to resist plant disease.

Vegetables require these fertilizer nutrients in high quantity, but take note that other minor nutrients such as iron, zinc, copper, and manganese may also be included in the fine print. Except for nitrogen and phosphorous, most of the nutrients stated can be found in the soil at sufficient amounts so adding unnecessary nutrients may cause nutrient imbalance. This is why the soil test is an important reference.

Common Mistakes Gardeners Make

Fertilizing vegetables with too much nitrogen — Are you using lawn fertilizers on your vegetable garden? Well, this is not recommended because lawn fertilizers are often high in nitrogen to make grasses green, lush and thick. Consequently, using lawn fertilizers on your vegetables may result to healthy leaves but less flower and fruit production. Applying excessive amounts of nitrogen may also increase insect problems and plant diseases. Moreover, many studies have shown that too much application of nitrogen to fruit crops like squash and tomatoes causes thick vines but no fruit. As for root crops such as parsnips, carrots and turnips, this may cause too much foliage production and no roots.

Applying phosphorous when it’s not necessary — This may increase chlorosis, a plant disease characterized by yellowing of leaf tissue due to iron deficiency. Absorption of unnecessary amount of phosphorous can halt symbiotic mycorrhizal-forming fungi that the plant needs and it also reduces the ability of the vegetables to absorb iron. Additionally, excessive amount of phosphorous shuts down the ability of the plant’s roots to produce organic molecules called phytochelates which increase uptake of iron.

Over-application of iron — This can cause micronutrient disorders.