It’s vitally important to have healthy soil to grow healthy produce…and a lot of it. To that end I will cover; Biochar, Blood Meal, Bone Meal, Coco Coir, Compost, Gypsum, Leaf Mold, Mulch, Peat Moss, Perlite/Pumice, Seaweed/Kelp, Vermiculite, and Worm Castings.
There is a big difference in the requirement and application for each amendment used; 1) raised bed, 2) in-ground garden. For raised beds you are starting from scratch and “building” your soil. For in-ground gardens you are “fixing” the soil you already have. Whatever the application, rich healthy soil gives you better tasting, healthier fruit and vegetables…from healthier plants.
So let’s go down the list…
Biochar –
Biochar is specially made charcoal used to improve soil. It is produced in a controlled low-oxygen heating process. 
Biochar is really helpful for sandy/native soils, dry climates, and where low organic matter exists in the soil. Biochar is helpful because biochar can help hold moisture, hold nutrients, support microbes, and reduce leaching. Think of it as tiny black porous sponge-like rocks full of microscopic holes. Those pores can hold water, hold nutrients, and shelter microbes which helps build long-term soil structure. Biochar can persist in soil for decades or even centuries. However, raw biochar can temporarily tie up nitrogen, absorb nutrients from soil, raise pH, and initially slow plant growth because it behaves like a giant empty sponge absorbing all that but releasing later over time. It is important to “charge” biochar first by soaking it in compost tea, mixing with compost, mixing with aged manure, mixed in with worm castings, or soaked with fish fertilizer…filling up the “sponge”…loading nutrients and microbes into the biochar before adding it to soil. Think of it this way…“Compost feeds the soil today. Biochar helps the soil hold onto those benefits longer.” Biochar is a helper not some miracle product
* I’ve used biochar this year…a fair amount actually. And no, I can’t see any improvement in the soil…it’s only been a month or two. But I have faith in the science of it.
Blood Meal –
Think nitrogen…it delivers it quickly. Blood meal is made from…you guessed it…animal blood from slaughterhouses. 
It’s sterilized, dried, and ground into powder. is typically 12–15% nitrogen, which is very high for an organic amendment. Nitrogen is what plants use to build, leaves, stems, and chlorophyll for photosynthesis. When plants don’t have enough nitrogen, they grow slowly and look pale. Blood meal can begin helping within days to a couple of weeks. It is also helpful when you have chunky compost. Blood meal will feed nitrogen to the microbes that are breaking down those woody chucks. Blood meal is not a general use soil amendment, it is a very specific remedy.
* When my greenhouse plants started to turn a bit pale, yellowing, and losing that bright lovely green…I added a treatment of the blood meal to each plant after watering well; and then watered it in again. The green came back within a 2 – 3 days.
Bone Meal –
Made from bones (mostly cattle) that have been steamed sterilized, then dried and ground into a fine powder. It is a 
great source for Phosphorus (10–15% normally) but where it really shines is calcium…high concentration of it. Phosphorus helps with root development, promoting flowering/blossoms, fruiting, and early plant establishment. A number of folks like to use it when planting tomatoes. The calcium availability can help with water uptake, and that can help with blossom end rot. Most raised bed soil, if done properly, doesn’t need bone meal.
* I’ve used this when planting tomatoes. I used it as a dusting in the bottom of the hole, the sides, and a top-dressing around (but not touching) the stem. Look at it this way…tomatoes need a lot of water. If a lot of water is available to the plant, but the soil calcium is low, the tomatoes can’t uptake the water as well. Bone meal can boost the calcium content of the soil potentially making more water available to the plant.
Coco Coir –
Is kinda like peat moss in some ways. It is made from the husks of coconuts. It improves the structure of soil, gives it 
water retention capability, improves aeration, which helps avoid soil compaction. It is often preferred over peat moss if the coco coir is quality, and not fresh. Look for a product that states “washed” or “buffered”. It also doesn’t add any nutrients to the soil. It is best when building the soil initially, not useful as a top dressing.
* I’ve not personally used this product but I hear great things about it. And the #1 thing I hear…it replaces peat moss and is a better product than peat moss.
Compost –
Compost is basically decomposed organic material made from things like: leaves/pine needles, grass clippings, fine 
wood chips, food scraps, and manure. When properly processed (over time, microbes break it down) into a dark, crumbly, soil-like material. When done correctly it becomes a slow-release, well-balanced nutrition source for your garden. It contains Nitrogen (N), Phosphorus (P), Potassium (K), and trace minerals…and usually microbes, beneficial bacteria and fungi if it wasn’t over processed. And I’ve found earth worms in some I’ve bought locally. Essentially compost is the bomb for gardens and raised beds. It is often the solution for any kind of poor soil, or soil that has been worn out over time. It holds water like a sponge, improves drainage, and prevents compaction. For plants it makes them more drought tolerant, better nutrient uptake, and healthier overall growth. It is really great when building soil for raised beds or improving ground-based gardens. It can also be used as a top dressing (usually ¼” – 1” depending on the plant variety). Don’t confuse actual compost with actual mulch…compost feeds, mulch protects.
* I am a great lover of and believer in compost! I have used it extensively to improve the soil here on the glamstead. To me…it is the ultimate soil “fixer-upper”. Like the ultimate general-purpose medicine that can cure anything that ails you. If you are blessed with the Midwest’s black soil called Mollisols, then you have the ultimate soil to grow pretty much anything. That is what compost is helping me to recreate here in my raised beds and to a lesser degree in my “in-ground” melon patch rows.
Gypsum –
Gypsum is a natural mineral (calcium sulfate) that is mined and comes in powder or granules. The #1 benefit of 
gypsum for gardeners is it can improve some clay soils, especially sodium-heavy or compacted soils. The #2 benefit is it will force out sodium from the soil.
* I used this on my yard…probably wasting my time. The application rate would have to be very high, like ¼lb per square foot. Why not effective? Besides my very low application rate, my soil is not high in sodium. Gypsum is best used when compaction is present and caused mainly by soil sodium content.
Leaf Mold –
Leaf mold is decomposed leaves that have broken down (fungal-driven) over time, usually 1–2 years. It is not 
compost…it comes from only leaves. Better than compost for water retention. Really improves soil structure…think aeration. Very low in nutrients but rich in beneficial fungi. It is not a fertilizer, it builds soil structure. It is really under-rated and under-used by gardeners.
* I’ve not used leaf mold and can’t really comment on it.
Mulch –
Mulch is essentially any material, organic or inorganic, placed on top of soil to protect and improve it. Yeah, you can 
include rock and plastic sheeting in the description. For me I am only referring to organic material such as straw, leaves, and wood chips. Mulch slows evaporation which then keeps soil from drying out too quickly. It also keeps soil cooler in hot days and warmer at night during cold/cooler nights…and that reduces plant stress…and that makes for healthier plants. It will also help reduce weed presence. I have found the best mulch is straw…clean, weed-free straw. I strongly avoid hay as mulch because…seeds galore…and it could have been treated with chemicals that will kill your garden for years. Finally, over time organic mulch will breakdown and improve soil structure.
* I’ve used mulch extensively in the past…and currently. It is a must in our area due to soil dryness and evaporation. But it is also extremely important in our area for sun protection. If the soil here is exposed to direct sunlight it “bakes”…yes, literally bakes. It gets so hot that you touch it and it is hot enough to cause pain. That kills a lot of the good stuff in soil such as microbes, worms, etc. And the surface of the soil gets to baked hard that when it does rain the water just runs off.
Peat Moss –
Peat moss is partially decomposed moss material harvested from peat bogs broken down over thousands of years. 
Peat moss can hold a lot of moisture. It loosens compacted soil and helps create kind of a fluffy root-friendly soil structure. Which makes it great for seed mixes and potting soil. It is acidic so it lowers pH. And that makes it good for blueberries and potatoes…somewhat. It is not ideal in huge amounts for everything. There is little to no nutrition in it; Coco Coir is a better option. Compost is the best alternative. Peat moss improves water holding — but compost improves soil life. Peat moss has fallen out of favor in recent years among some gardeners.
* I’ve used peat moss a lot over the years, far less this year than previous years. Why? I am switching over to using more compost that peat moss. And where I need more “life” in the soil…worm castings is for me. I’ve used peat moss when starting seeds…and will continue to do so as part of the seedling mix.
Perlite/Pumice –
Perlite is expanded volcanic glass; basically volcanic rock heated until it “pops” like popcorn. Which in turn creates 
lightweight white porous particles. Improves drainage, adds air pockets (roots need oxygen), and reduces soil compaction (add a bit of fluffy to the soil structure). No real nutrients; it improves the physical soil structure. Normally, compost is usually a more valuable option. Vermiculite is an alternative. Vermiculite is not as good with drainage, but better at water retention. Pumice is pretty much the same as perlite…used interchangeably. The biggest advantage to pumice is its weight. Perlite is very light and will float and/or blow away; pumice is heavier and will stay put longer. It also keeps its structure longer as well.
* I’ve used perlite a lot and will continue to do so in the right application requirement. I’m not real crazy that it floats and can blow away. It is good in seedling mix. I’ve not used pumice and no intention to use it in the future but it is a valid option to avoid it blowing away.
Seaweed/Kelp –
Kelp/seaweed is made from ocean seaweed, usually kelp. “It is used primarily as a liquid fertilizer—not a heavy 
fertilizer—but as a source of micronutrients and trace minerals.” It helps plants handle heat, drought, transplant shock, and other environmental stresses. For root development kelp can stimulate root growth and branching. It is really good for seedlings and transplanting. And it is a boost for microbes, especially when you combine it with compost and/or worm castings. Look at kelp as more valuable as a plant health “tonic” than as fertilizer.
* I’ve not used seaweed based fertilizers so I have no first-hand experience with it.
Vermiculite –
Vermiculite is actually a naturally occurring mineral heated until it expands into lightweight flaky particles/granules. 
Vermiculite absorbs a lot of moisture, more than perlite or pumice. Unlike perlite, vermiculite can retain nutrients somewhat which helps reduce nutrient leaching out of the soil. When seed starting it is excellent for germination and keeping seeds evenly moist…great in seed-starting mixes. The downside…too much vermiculite can reduce oxygen and create soggy soil. Great for sandy soils as well…holds in moisture and releases it slowly. Compost, mulch, and worm castings are alternatives to seriously consider. Comparison…perlite fights soggy soil, vermiculite fights dry soil.
* This year I really started using vermiculite and I love it. It is a perfect product to help with our sandy soil. The first time I used was about 17 years ago when I planted a pine tree in horrible dead compacted sandy soil. I used the large granular variety and it was amazing! Made a huge difference in the soil and the tree grew like crazy.
Worm Castings –
Worm castings are basically premium compost processed through earthworms. Process is worms eat organic 
material, microbes help break it down in the worm’s digestive system, and then worms excrete highly stable nutrient-rich material. Yup…worm poop. Worm castings are very gentle and they are beneficial to microbes, soil “life”, and nutrient cycling adding to long-term plant and soil health. Worm poop contains microbes, enzymes, humic substances (humic substances formed from long-term decomposition of organic matter…ancient plant material and other composted organic matter), and nutrients. For seed starting it is fantastic! For transplant recovery it is awesome. Compared to compost…compost feeds the soil, worm castings supercharge the soil.
* This year was the first year using worm poop. I really like the stuff. I’ve used organic 100% worm castings that I bought from Lowes and Home Depot…both are great, both worked, Home Depot was a bit less expensive…$1.67 vs $1.87. I bought a bag from Amazon about $1.10 per pound in a 40lb bag. The stuff from Amazon was also organic, but I had “Worm Egg Material” in it as well. The product emphasizes that the worm eggs are the cocoons worms lay plus tiny balls of soil and bedding bits not eaten by worms, designed to enhance microbial activity in your soil. In the product description; “A Chance for Worms – Worm eggs may hatch in soil, adapt, and begin to help improve soil quality.” So I have no problems or issues with the addition of the “Worm Egg Material” in with the organic worm castings…might actually be better due to the chance of worms hatching.
NOTE: “These are my experiences and observations gardening; results may vary depending on climate and soil conditions.”
In the next article I will talk a bit about how I mix different amendments.
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