Series: Free Organic Gardening Course
- What Is Soil Made Of And How Does Soil Form?
- Home Soil Testing – No Need For A Soil Test Kit
- How To Prepare Soil For A Garden – 2 Different Ways
- Soil Sample Testing – How To Take A Soil Sample
- Natural Organic Fertilizers – How To Choose For Your Garden
- Organic Garden Pest Control – Without Toxins
- Organic Weed Control – Kill Weeds Naturally And Forever
- Organic Composting 101 – Making Compost Better
- Worm Bin Composting – How To Build A Worm Compost Bin
- Homemade Fertilizer – 2 Great Easy-To-Make Fertilizers
- Cover Crops For Gardens – Build Soil And Control Pests
- Soil Inoculant For Plant Nutrition (And Fewer Pests)
- Permaculture Principles – A Few Tips For Your Garden
- How To Make Your Own Garden Inoculant For Less Than $1
- How To Plan A Landscape Design – 6 Steps To A Good Garden
- Seedbed Preparation, Sowing Seed And Planting Vegetables
- Want To Grow Organic Food? Here Are Some Tips
- Forest Gardening – How To Grow A Food Forest
- When Gardening Organically, You Need To Think Differently
There are a handful of very useful natural organic fertilizers for you to choose from, especially if you look online.
The hard part is knowing which ones to choose, but I’ll give you a few things to look for.
Natural organic fertilizers don’t look like much of a bargain compared with the high nitrogen-phosphorus-potassium numbers on chemical fertilizers, but they’re so much more valuable.
They often provide many more nutrients than just N-P-K, they don’t hurt soil life, and it’s generally better to add lower doses of fertilizers anyway.
What Is A Natural Organic Fertilizer?
When I say organic, I just mean anything that would be allowed on an organic farm or organic garden.
Most of the regulations come from organic farming, and they help inform us organic gardeners.
You don’t want something with a label that says ‘organic-based,’ as that’s mostly chemicals.
I know we’re talking about natural organic fertilizers here, but the words natural or environmentally-friendly on a label aren’t regulated, so they don’t really mean anything.
They’re not bad, but you shouldn’t buy just because a label says natural.
If you don’t know much about ingredients, it may be easiest to get something that is certified organic or OMRI Listed.
That’s a good start, but even then, how do you know which ones to get?
Mineral Organic Fertilizers
Mineral means rocks, like calcium carbonate (lime) or glacial rock dust. These are the soil builders.
The rock dust has lots of different minerals and it’s a great natural organic fertilizer to apply without even needing a soil test. It can be a nice soil fertility builder.
Most of the others like lime or rock phosphate or greensand provide high amounts of just a couple of minerals.
That means they should usually only be applied if you know you need them, which usually means getting a soil test from a reputable organic soil lab.
A downside of mineral organic fertilizers is that it can be difficult to find the ones you need, so you do need to be patient and try to find an organic fertilizer supplier or farm supply store.
Bottom line: go ahead and use rock dusts, but hold off on the specific minerals until you do a soil test.
Biological Organic Fertilizers
Biological basically means anything that was once living. These can be soil builders, but they’re generally more for fast, short term nutrition.
Some of the most popular of these are seed meals, but most of those are now derived from genetically-modified plants.
Now that may not be a big deal, but they’re not allowed in organic farming, and I don’t really want to support the GM movement, so I do my best not to use them.
Just as an organic fertilizer, they work fine – not sure yet if there are consequences to the planet. I’ll admit I’m more strict on this than most organic gardening experts.
Fortunately there are other excellent biologicals which have given me great results. Most of them have small amounts of many dozens of nutrients, so they can be applied without a soil test.
Seaweed and molasses are all great. Fish is a good organic nitrogen fertilizer, although a lot of products aren’t as sustainable anymore because the little fishies in the oceans are dwindling rapidly.
Ocean water (direct or in a concentrated product) is one of the best organic fertilizers and I consider it a biological even though it’s just seawater – there is certainly biology in it.
The nice thing about all of these is they’re easy to find online, and they’re inexpensive both to buy and ship.
Blended Organic Fertilizers
Many of the natural organic fertilizers you’ll find will be blended fertilizers, which is usually a combination of several minerals (like lime) and several meals (like cotton seed or feather meal).
If you use just a little, they might be alright, but they’re probably not the ideal product for your organic garden.
Other than the GMO seed meal issue, it’s mainly because you almost certainly don’t need all of the mineral fertilizers in them.
If they have dolomite and rock phosphate and greensand, you’re bringing in calcium, magnesium, phosphorus and potassium (among other things).
Sounds great on the surface, but the way to create great soil is to get to a certain balance of these nutrients rather than just increasing them all blindly, which causes many problems.
That’s why I recommend soil testing before adding specific minerals, and also using less concentrated liquid organic fertilizers in the biologicals.
Feel free to ask your organic fertilizer questions below, or let me know your favorites…