Organic Fertilizers

Many different organic fertilizers that we can use in our vegetable garden. We're going to take a look at a number of these, but first I want to look at our soils. Promoting healthy soils is the best way for us to promote healthy plants, and organic matter is the key to healthy soil. There's several ways we can add organic matter, mainly by mulching the surface. In the springtime, when I'm getting plants started, what I like to use is compost because it's dark and it helps the soil, the sun warms it up, it helps it get nice and warm as we transplant or put seeds in the ground. Compost adds a lot of organic matter to the soil. We can also use a variety of mulches. On these beds I have some cottonseed hulls, and these are lighter in color, and they're a good choice in the summertime when you don't want the soils to be quite as hot. You can also use straw or hay, and one of the things I really like to do is when I harvest a crop, or this one happens to be our cover crop, I just lay the cut material right on the surface, and it acts as a mulch, it helps retain soil moisture and keep the weeds down, but more importantly, it'll decompose and add nutrients right back into the soil. There's a lot of ways to encourage organic matter. Organic matter does a number of things. It's going to provide essential nutrients to the soil. It's also going to help maintain moisture in the soil. It creates pores for good drainage, so it's kind of the best of both words. It holds moisture, but it also provides excellent drainage. Now when we look to fertilizers, when we need to add some additional nutrients to the soil, with organics, we're going to look for the same things we do with traditional fertilizers. You're going to find three numbers on your fertilizer container, and these represent the ratio of nitrogen, phosphorus, and potassium in that order. It's important to know, because different organic fertilizers have different ratios of these three elements, it's important to know what you need for your situation. So you want to start, of course, by conducting a soil test, and that'll tell you what's existing in your soil, how much nitrogen, how much phosphorus. It'll also tell you the pH, which might affect the type of fertilizer you use. You also need to consider the plants that you're covering. The different elements affect plant growth in different ways. Nitrogen promotes lush green growth, and we use a lot of nitrogen on our greens crops, our lettuce and spinach, as well as our herbs, because we're harvesting that foliage. Now other plants won't produce as well if they have too much nitrogen. Okra and sweet potatoes are good examples. If you get too much foliage growth, it'll be at the expense of fruits or tubers in the case of the sweet potatoes. Now phosphorus promotes flowering and fruit development, and potassium, which we sometimes see labeled as potash, will promote bright, colorful flowers, which is great in your ornamental beds, and overall plant growth. But it's important to note that oftentimes phosphorus and potassium are already available in the soil, and sometimes even available at excessive amounts, and that's why that soil test is very important. Now organic fertilizers and inorganic, or our traditional fertilizers, come from different sources. Organic fertilizers are derived from decomposed animal or plant parts, while our traditional fertilizers are generally synthetic chemicals. And there's an advantage to having these fertilizers that come from decomposing material. One we have that organic matter, but more importantly we have a rich source of nutrients. Organic fertilizers also often have microorganisms, and these are bacteria, tiny insects, which help promote soil health. As with our traditional fertilizers, we have a wide selection of both powder or liquid forms of fertilizer to choose from, and we're going to look at a few of these. The first is cottonseed meal, and this has a blend of nitrogen, but it also contains phosphorus and potassium as well. And you want to be careful, you don't want to just use any cottonseed meal, because most cotton crops are treated with herbicides and pesticides, so you want to make sure that you're purchasing a cottonseed meal that's specifically for use as a fertilizer. Another common fertilizer is blood meal, and this is a very rich source of nitrogen. As you can imagine from the name, it is made of blood, it's a byproduct that is collected from slaughterhouses. It's a really rich source of nitrogen, and you want to be careful to not over-apply it. It's easy to actually burn plants by putting too much nitrogen, so wonderful for a garden where you don't want to add phosphorus or potassium. We've had soil tests indicate that in our garden we have a lot of phosphorus, so this is going to be my choice to get the nitrogen I want without having other compounds added. Now bat guano is a fertilizer that's been used by farmers and gardens for centuries, and it is the excrement of bats, and it's collected from caves where bats tend to group together to sleep. And this is another wonderful source of nitrogen, it also has trace amounts of phosphorus and potassium as well. A lot of people who are animal enthusiasts are concerned about the bats, but you can find bat guano that is certified to be bat friendly, so you want to look for that when you're selecting your fertilizer. Now there are many different products that are derived from the ocean, mainly from fish, which would be byproducts of the fishing industry, but also from kelp and seaweed. And these will come in a liquid or in a powdered form, and these are a wonderful source of nitrogen as well as trace minerals, micronutrients, and these are very fast acting, the nitrogen is immediately available to plants, and so it's a real popular choice among organic farmers. And a lot of times we'll mix this right into your irrigation, or you can apply it as a foliar spray as well. Another fertilizer that's received a lot of attention are the compost teas, and just like it sounds, they are pretty much like a giant tea bag full of compost, and you soak these in water and it'll take a few days to steep. Now you can also, you can purchase these ready-made mixtures, or you could mix your own compost and let it sit in water, and as it sits and steeps we're going to end up with a highly concentrated tea, very rich in nutrients, and a wonderful soil application, or again a foliar application as well. In addition to being a wonderful source of plant nutrients, there's evidence that compost teas also suppress disease and fight toxins. I have another animal product, we have some worm castings, and this is another one that's getting a lot of attention. You'll see worm castings, you might see vermicompost or worm compost, they're all very similar, and these are the compost that you would collect if you were using worms to make your compost, and this is another very rich source of nitrogen. And what we'd want to do with this is top dress it, but you only want to apply a small amount because it's very rich. You can work it into the soil if you're amending your soils, or you can use it in your containers, either sprinkled around the surface or mix it right into your soil mix. The last product I want to look at is actually not a fertilizer, it's a soil inoculant, and this contains mycorrhizae fungi, and our legume plants, beans, peanuts, peas, they have a symbiotic relationship with soil-dwelling fungi, and when we have disturbed soil, such as through tillage, or if we're establishing a new garden, those mycorrhizae might not be present in the soil, so we could get our plants and our new beds off to a good start by mixing a little bit of soil inoculant into that soil. Now whatever your choice of fertilizer, there's a few things you want to keep in mind. Organic fertilizers tend to be slow-acting, as a general rule, the fish and kelp might be a little quicker, but compared to our inorganic fertilizers, which have more of an immediate effect, these need to be decomposed a little bit by soil microorganisms before the nutrients are available to plants, and different environmental conditions will affect how quickly that happens. If it's very dry in our garden, or if it's very cold, like in the early spring, those microorganisms will be less active. So you want to keep that in mind, that it takes time to reap the benefits from our organic fertilizers, but they are very long-lived, and they will be a wonderful, slow-release, long-acting fertilizer for your garden.