| Feed the Soil and Feed the Leaves. |
While there are no absolutes in the garden, I think it is safe to say that most of us (and maybe all of us) place our primary focus on feeding the soil. This is as it should be since plants receive most of their nutrients through their root system. But there are many benefits to periodically making a foliar fertilization in addition to our regular gardening practice of soil fertilization.
There isn't anything complicated about foliar feeding – it is simply the application of fertilizer to the leaves of plants. When you are considering a foliar application, it is important to understand that foliar applications are not practical for nutrients that plants require in large amounts, such as nitrogen, phosphorous, and potassium (the N-P-K that is likely on your fertilizer package). Nor is foliar feeding normally the most effective method for delivering immobile nutrients such as calcium and boron.
So why do a foliar feeding at all? A foliar feeding helps address the immediate needs of the plant. The primary benefit of foliar feeding is that it is the fastest way to deliver a corrective infusion of micronutrients. There is also evidence that a periodic foliar feeding will increase the activity in the leaves, increasing chlorophyll production and photosynthesis which drives increased water and nutrient uptake from the soil.
How does that work? Plants absorb the nutrients through small openings on the stems and leaves called stomata. Research shows that plants absorb fertilizers faster through the stomata on their leaves. This makes the leaves an ideal point of entry for the micronutrients that can be difficult to pull out of the soil. The stomata close when temperatures reach 85° F and so foliar sprays should be applied early in the morning before temperatures rise.
Another scenario where foliar feeding can be especially helpful is in areas where the soil conditions limit the availability of nutrients. For instance the soil where I live contains a lot of calcium carbonate. Calcium carbonate inhibits a plants ability to absorb iron and manganese – for me, foliar feeding iron and manganese is a great method for adding these nutrients to my plants.
Foliar fertilizers can be applied more frequently than soil fertilizer. The frequency is dependent upon the plant type(s) that you are growing:
• Annuals every 3 weeks
• Fruit every 3 to 4 weeks
• Perennials every 6 to 8 weeks
• Vegetables every 1 to 2 weeks during the growing season
Blossom end rot is related to a lack of calcium in the plant and occurs most frequently in tomatoes and peppers, but can also affect apple trees. To combat this problem, use a foliar application of calcium or a water soluble fertilizer that contains calcium to begin the process of getting the plant back on track.
This table highlights the advantages of the products we recommend for foliar applications. Use the table to help you decide the product that best meets your needs.
|Product ||Advantages |
|Fox Farm Big Bloom ||N-P-K of 0.01-0.3-0.7 |
|Odorless and gentle for delicate plants |
|Derived from bat guano, earthworm castings, rock phosphate, and Norwegian kelp |
|Plant Solution ||N-P-K of 2-0.6-2 |
|Has a pH of 3.8 and can lower the pH of tank mixes |
|Contains calcium, magnesium, iron, manganese, sulfur, and other trace minerals |
|Maxicrop Soluble Seaweed Powder |
Maxicrop Liquid Seaweed
|N-P-K of 1-0-4 |
|Seaweed powder ships dry powder - save on shipping! |
|Contains more than 70 minerals, vitamins, and enzymes |
|Derived from Norwegian seaweed |
|Maxicrop Liquid Fish Fertilizer ||N-P-K of 5-1-1 |
|Made from Atlantic fish and contains natually occurring amino acids as well as B vitamins |
|Nitron Formula A-35 ||N-P-K of .09-.12-.02 |
|Contains calcium, sulphur, magnesium, manganese, zinc, iron, boron, and copper |
|Bountiful Harvest ||Contains boron, iron and zinc plus amino acids |
|Growth stimulants from naturally occurring bacteria and fungi |
|Bioform ||N-P-K of 4-2-4 |
|3% sulfur helps lower the pH of soil |
|Derived from fish hydrosolate with bone meal (for calcium) and molasses (for microbial stimulation) |
|Neptune's Harvest Fish ||Nutrients are chelated for easier absorption |
|Screened to 150 micron mesh for clog free use |
|Derived from fish protein |
|Neptune's Harvest Fish and Seaweed ||N-P-K of 2-3-1 |
|Nutrients are chelated for easier absorption |
|Screened to 150 micron mesh for clog free use |
|Combines fish protein and seaweed in one application || |
| ||• || Use only water soluble products as foliar feeds. |
|• ||Foliar feeding only works on actively growing plants – don't use on dormant plants. |
|• ||Test the product you are using with a first application mixed at 1/3 the recommended rate. |
|• ||The law of little bits applies! It's better to spray small amounts of mild mixtures. |
|• ||Remember that nitrogen may burn the leaves – always test first on one leaf. |
|• ||Make sure that temperatures are below 85° F when you foliar feed. |
|• ||Don't spray at night if possible; late evening sprays can create a situation for powdery mildew. |
|• ||No matter the temperature – don't spray when the plants are in direct sunlight. The water beads act like prisms and may burn the leaves. |
|• ||A wetting agent such as Therm X™70 will help the fertilizer ‘stick’ to the leaves until the good stuff can be absorbed. No more beading up and rolling off! |
|Your Plants Will Love Our New Neptune's Harvest Fish & Seaweed Liquid Fertilizers! |