Fertilizers for Vegetables
The nutrient needs of vegetable plants change not only with the species and variety, but also with time. Growers can never know exactly how much of each nutrient a vegetable plant will be looking for and when, so it is essential to have all nutrients present and available in the soil all season.
The chart below was generated by field experiments conducted by D.O. Huett with Flora-Dade tomatoes in Australia, during an extensive 1985-1988 research project, to examine the effect of Nitrogen and Potassium on fruit yield and quality. Despite its age, this study’s results are still widely used because the high number of plants tested.
Source: Huett, 1985
As seen above the amounts of Nitrogen (N) and Potassium (K) used by the tomato plant increase much more rapidly than Phosphorus (P), Calcium (Ca) and Magnesium (Mg) as harvest time approaches, but none of these are steady or predictable changes. Nitrogen needs actually decreased by nearly one-half after transplant and before flowering!
How can a grower be sure that the needs of their crops will be met all season? How can we continue to feed these nutrients when roots may be under a weed barrier and side-dressing is not an option? Can foliar feeding and fertigation through drip irrigation supply nutrients in these quantities?
Remember that the numbers listed on fertilizer bags are percentages of total weight. For example our Re-Vita Pro 5-4-5 is 5% Nitrogen, 4% Phosphorus, 5% Potassium and 8% Calcium minimum. So if you apply the minimum recommended amount for vegies of 400 lbs. per acre, you would be applying 20 lbs. of Nitrogen, 16 lbs. of Phosphorus, 20 lbs. of Potassium and 32 lbs. of Calcium per acre.
In comparison, most organic liquid fertilizer is around 3-3-.3. In order to apply the equivalent amount of Nitrogen and just a bit more Phosphorus, you would have to apply 78 gallons per acre (at 8.5 lbs. per gal.). To get the same Potassium you would have to bump that to 784 gallons! Applying granular fertilizer pre-plant is by far the most cost effective approach to ensuring needed nutrients are available all season. Fertigation and foliar spraying are important and proven techniques for feeding micro nutrients but should not be your only source of nutrients. As seen in the chart above plants have needs that must be met.
We realize that organic growing is not all about dumping nutrients into the soil. To be done right, organic growers must balance soil and encourage the abundance of microbial life to deliver nutrients and build soil organic matter. All of our Re-Vita fertilizers are designed to maximize the efficiency of “mineralization” by soil microbes into plant-available nutrients. By adding kelp and humate to Re-Vita, we ensure that needed carbon, micro nutrients, minerals, growth stimulants and humic acid are present in the root zone. In addition, Re-Vita’s main ingredient is composted layer manure, naturally containing 8% calcium and full of organic matter and slow release nutrients. We compost the manure using the wind row method for around 7 weeks to concentrate nutrients and cultivate the beneficial microbes. Re-Vita fertilizers are the culmination of old-school farming practices and new age technology.
At Ohio Earth Food we believe in time-tested agronomy backed up by decades of research. We recommend a 4-step approach to growing vegetables that will feed your plants and microbial life for healthy soil at prices that will allow for a healthy return on your investment.
- Test soil and work to balance and maintain levels of cations, macro and micro nutrients while continually building levels of organic matter.
- Start your seeds in a premium potting soil like Plant Pro or The Seed Catapult.
- Apply hardy doses of slow release, complete fertilizers like our Re-Vita blends and AZOMITE before you work your soil for the last time, before you lay plastic for vegetables, or at planting for row crops. These granular fertilizers are designed to flow through your equipment.
- Develop a foliar spray and fertigation regiment that mixes preventative disease and insect control with soluble and liquid products like Jumpstart, Jumpstart II, Premium Cal 33, Soluble Fish with Crab, Organic Gem, Stimplex and Maxicrop Soluble Seaweed Powder. You will find a liquid or soluble product to provide nitrogen, phosphorus, potassium, calcium, boron and all other needed nutrients that is approved for certified organic use on our Foliar Sprays page.
We work closely with customers to identify your needs and have found or make products to fill those needs and test them to be sure that they work.