Organic fertilizer is a bit of a funny concept (well, it’s funny if you’ve been hanging around chemical farmers for a while) but here’s what you need to know.
Feed the Soil
In the organic gardening world, we focus on feeding our soil and not our plants.
Feed the soil properly and it will take care of growing a healthy plant. Why did I italicize “healthy”? Because you can grow a bigger plant with chemical fertilizers. And you can likely grow more of them in a smaller area if you load them up with chemical fertilizers. But you can’t grow as healthy a plant with chemical fertilizers and that’s the point of this article.
Stress Free
Organic gardening doesn’t stress the plants like chemical gardening does. The plants are healthier and much more insect and disease resistant. Given that insects attack weak plants that are out of balance, one of the primary benefits to organic gardening is that your garden takes care of the vast majority of the insect problems.
Stressed plants – plants that are being pushed along too fast with too much fertilizer will develop more sugar in their leaves as a stress response. Insects are attracted to leaves with more sugar (seems that insects have sweet tooths) š So if you push your plants along with chemical fertilizers you’re going to get bigger plants but you’re also likely to get more insect problems.
And in the concentrations of insects you’re going to see, it is almost a certainty that you’re going to have to spray (hopefully organic but often a beginning gardener will be seduced by chemicals for their quick fix).
So overfeeding creates the conditions that will tempt you to spray chemicals on your garden.
Organic Soil Fertilizers
All numbers are approximate, and will vary with source and method of preparation
Blood Meal contains approximately 12% nitrogen, 3% phosphorus and just
under 1% potash.
Bone Meal – 3% nitrogen, 23% phosphorus, negligible potash
Cottonseed Meal 7% nitrogen, 0 phosphorus, 2% potash
Grass Clippings 1% nitrogen 2% potash
Manure
- **dried: 1% nitrogen, 1% phosphorus, 2% potash
- **fresh: depends on the animal but 2% nitrogen, 1% phosphorus, .5%
potash
Wood Ash 0% nitrogen, 1% phosphorus, 7% potash. Very alkaline and can
burn plants.
But given the choice, imho compost is still the best organic fertilizer.
What would be a non-animal phosphorous addition to cottonseed meal? Can’t use animal products in garden because my dogs will eat them including dirt even when they are well mixed in.
Rock phosphate would be your first choice – or actually your second over something called “soft rock phosphate” that is “said to be” softer and more easily/quickly broken down in the soil. Either way, I doubt the dogs are going to eat it (having said that, we had a lab that would eat anything – and I do mean anything) š Here’s a link to Amazon that will get you started. Note that rock phosphate is not going to very quick acting (but then again, most phosphorus sources aren’t) so do not expect any quick changes in plant growth. It’s one of those things you do on a regular basis and dig it in (remember phosphorus isn’t highly mobile in the soil) for best results.