Many gardeners must supplement the natural supply of nutrients in their vegetable garden soil with both organic and inorganic fertilizers, to meet demand.
Fertilize according to your soil test results and plant needs. Vegetable crops often deplete their environment quickly, so additional support may be necessary.
Soil Tests
From seedlings to mature crops, vegetables require essential nutrients in order to thrive and flourish. While most plants receive their nutrition directly from the soil they were planted in, vegetables must receive additional fertilizer applications for proper development and growth. Unfortunately, soil tests cannot accurately pinpoint what kind of fertilizer would best meet this need.
Soil tests measure plant-available nutrient levels and recommend lime and fertilizer application rates accordingly. They also evaluate physical properties like humic acid content and exchangeable acidity, to provide further recommendations. Most tests involve taking a moist soil sample from the topsoil at 6-8 inches depth and placing it into a clean bucket, to avoid contamination with metals (e.g. brass, bronze and galvanized tools). A clean plastic container and stainless-steel probe is often recommended for this task. Once soil has been collected in a probe, it should be mixed thoroughly to create an evenly mixed representative sample from all areas or fields to be tested. Once collected, laboratory analysis should take place within two or three weeks of collection of sample.
Nitrogen, phosphorus and potassium are the three essential nutrients for vegetable gardens. Other essential nutrients like iron, copper and manganese may also be required in smaller amounts; it’s important that additional supplements such as these only be added if a soil test indicates this to avoid imbalanced soil conditions that lead to deficiencies among vegetables plants.
A soil test will show if adding lime is required to adjust the pH levels in your soil and what rate this should occur at. Furthermore, testing can show whether your soil has insufficient phosphorus, potassium and calcium content; and indicate any deficiencies which exist in these elements that need replenishing through adding them back in as part of its makeup.
A soil test recommendation will outline exactly how much of each nutrient should be applied per acre. If the soil varies significantly, however, you may wish to divide the field into sections and test each section separately – this way you can treat different parts of your field differently without as much variance from using just one soil sample as representative of an entire field.
Types of Vegetables
Vegetables provide essential vitamins and nutrients. If you’re growing them yourself or admiring those of your neighbors’ gardens, using simple fertilizers will give your vegetable plants an ideal start and encourage lots of growth for tasty veggie harvesting!
Vegetables can generally be divided into five classes of edible plant parts: root, tuber, leaf or leafstalk, flower and fruit. Root vegetables include carrots, beets and radishes while tubers include potatoes and sweet potatoes. Leaves include asparagus, kale, Swiss chard Swiss chard as well as leafstalk vegetables like Swiss chard. Flower vegetables such as broccoli cauliflower artichokes as well as tomato peppers cucumbers squashes which while technically fruits but often considered vegetables due to their savory qualities.
Step one in selecting and applying fertilizers to your vegetable crop is testing its soil. Soil testing services such as UNH Cooperative Extension offer this service; once tested, follow general recommendations for fertilizing your garden.
Organic granular fertilizer with an NPK ratio such as 10-10-10 or 5-10-5 is usually recommended for vegetable gardens. These formulas provide all three primary plant nutrients – nitrogen, phosphorus and potassium. However, certain vegetables require more or less of each nutrient than others so make sure you purchase the most suitable product for your plants.
Vegetable crops get their nitrogen needs met primarily from decomposing organic matter in soil, with increased needs as plants begin to flower and produce seed – at this stage supplemental applications such as beans or melons become necessary.
Peas and soybeans, for instance, can fix their own nitrogen supply by attaching it directly to their roots, requiring only minimal external sources for nutrients. Leafy greens such as lettuce and spinach also only require minimal extra nitrogen; these plants can obtain their supplement either through planting time granular organic fertilizer applications or water-soluble products mixed into regular irrigation programs.
Heavy Feeders
Most vegetables fall under the category of “heavy feeders,” meaning they require substantial nutrients from their soil during their growing period. Heavy feeders include brassica crops such as broccoli, cauliflower and brussels sprouts as well as leafy greens such as lettuce. While nitrogen is necessary for healthy foliage production, phosphorus and potassium also play an integral part. Nightshade family plants such as tomatoes peppers and eggplant also demand nutrients; in their case phosphorus helps build strong buds while nitrogen promotes dense foliage growth. Root veggies such as carrots parsnips and radishes require less nutrients from their soil-grown environments than their brassica counterparts do.
Before purchasing fertilizer, read carefully over its label. Three numbers on a package represent the ratios of nitrogen (N), phosphorus (P), and potassium (K). Most all-in-one vegetable fertilizers tend to contain high levels of N while low P and moderate K content – an optimal fertilizer will correspond with your soil test results ideally as excess N can lead to leggy plants with excessive foliage while an abundance of P or K could result in chlorosis.
Ideal soil tests should be conducted a year prior to planting your vegetable garden, giving the ground time to recover from last year’s vegetables which depleted nutrients in the ground. You can conduct home tests yourself using kits available online, or send off samples directly to a Cooperative Extension office for more accurate results.
As you learn to fertilize your vegetable garden, crop rotation is crucial and using chemical fertilizers should be limited as much as possible. Allowing one plant variety to remain in one spot over time can deplete its nutrient levels and prevent healthy development – the more informed you become about both soil composition and vegetable varieties, the greater will be your success with gardening efforts! Wishing you success!
Light Feeders
Plants need various nutrients in order to thrive and produce nutritious vegetables. A soil test can provide you with insight into which nutrients already exist in the soil and how much supplemental fertilizer would be necessary to bring it up to desired levels. There are numerous synthetic and organic fertilizers on the market; most contain analysis reports so you can quickly see exactly which nutrients are present within.
Crop rotation can help balance your vegetable garden by planting different vegetable crops in each season and rotating between heavy feeders like corn and legumes with soil-nourishing crops like onions. Rotating vegetables helps prevent depletion of soil nutrients as well as decrease pest and disease issues in your garden.
For your vegetables to thrive, they require soil that is rich, evenly moist and well-drained. Although vegetables tend to be light or moderate feeders, they still require plenty of organic matter and adequate levels of nitrogen, phosphorus and potassium in order to thrive.
Heavy feeders need an abundance of nutrients in order to thrive and produce fruit, quickly depleting soil nutrients. Heavy feeders also tend to require more fertilizer than lighter or moderate feeders and are more vulnerable to pests and diseases. Solanum or Nightshade family vegetables such as tomatoes, peppers and eggplants as well as Brassica vegetables like broccoli cauliflower kale and brussels sprouts fall into this category of plants with excessive needs.
Legumes are prolific feeders, but they also contribute a tremendous amount of nitrogen to the soil. Legumes are known as nitrogen-fixing plants – taking airborne nitrogen and turning it into usable form that other plants can utilize before returning it back into the ground, maintaining equilibrium in its fertility levels.
Light feeder plants include leafy greens, squash and cucumbers, radishes and root crops like carrots and beets. These types of plants require very little fertilizer and can tolerate some drought conditions; they thrive best in well-drained soil with plenty of organic matter; light feeders may be more vulnerable to insects so mulching might be useful; fast-acting liquid fertilizers also work very well in this regard.