By Stephen Legaree of Alberta Urban Garden Simple Organic and Sustainable
How to build soil fertility for the perfect garden soil for free! It is fall here in Alberta and that means the summer crops are done and some of the garden beds are done for the year. Just because there is nothing goring in some of these beds does not mean you can’t be getting ready for next season. Today I am going to show you how I continue to build soil fertility over the winter with free and local resources. Mulching garden beds is a great practice to help build your soil fertility.
Compost Probably the best thing to mulch with is finished compost. The nutrients are immediately available for the nutrient cycle and it usually comes with a high concentration of beneficial bacteria and organisms like earth worms that will help break down the other mulch materials. Generally I simply lay it on top in a 2-3 cm or 1 inch layer after having pulled back any undecomposed mulch material. I don’t mix it in so that I don’t damage any of the beneficial organisms like fungi in the soil.
Autumn Leaves Autumn leaves are a great resource that quite literally falls from the sky. They have a wide variety of trace elements and carbon. In fact of the 15 commonly tested for beneficial and essential elements autumn leaves have 11/15. When broken down they add these nutrients to the nutrient cycle and the carbon material adds humus that retains water and provides habitat for soil born beneficial organisms.
I usually add a thick layer to the garden as it will help insulate the soil from the harshest winter temperatures. By spring the volume will have decreased as it decomposes. The one thing autumn leaves don’t have a lot of is Nitrogen for this we will need to turn to some other resources you generate in the kitchen
Used Coffee Grounds and Tea Leaves Used coffee grounds and tea leaves are often tossed in the trash but they are a valuable resource to add to the garden. When I analyzed coffee grounds in the testing garden assumptions series videos I found they had a total NPK of 2.05-0.2979-0.7469 with a hand full of trace elements.
Used Tea leaves also have an impressive total NPK of 4.15-0.62 -0.4 doubling the nitrogen and phosphorus of used coffee grounds  Tea leaves also have 12 of 15 elements making them a valuable addition to the mulch. I usually sprinkle them directly on top of the autumn leaves making sure not to apply more than a cm or ½ inch to any one area. If over applied they can slow the decomposition process. Not only can you take materials that would otherwise become trash but you can literally grow your own fertilizer on site.
Comfrey Comfrey is a plant that sends down a deep taproot to and is able to collect nutrients from the mineral layer and bring it to the surface as a part of its leaves. I use the leaves as a part of my mulch layer helping to deposit those nutrients where the garden plants can use them. Comfrey has a total NPK of 3.7-1.2-8.43 and it contains all 15 of the 15 commonly tested for essential and beneficial elements.
Eggshells Eggshells are commonly added to my mulch layer as well. They are over 40% calcium that is immediately plant available when released from the shell. Eggshells also have a wide variety of elements including nitrogen. They have 9/15 elements tested for and most importantly have significant quantities of Selenium which is often not in other free and local resources. Eggshells are easy to add to the mulch layer. I usually let them dry out in my shed for a few months. This will help reduce any potential for harmful bacterial to colonize. Once dry and brittle I crush the shells roughly and simply sprinkle on the mulch layer.
Hot Compost If you are applying mulch to an area near a live plant make sure not to apply too thick of a layer of these mulch materials. When combine in larger quantities they can and will create a hot compost that can damage root systems.
Cover Crops, Wood Ash and Urine When combine and used in a mulch layer or in the creation of compost these free and local resources often have more than enough nutrients allowing you to grow healthy organic vegetables year after year. If combine with other free and local methods such as cover crops, wood ash and human urine I am confident anyone can have a product free garden that produces healthy organic crops.
If you would like more information on the materials above make sure to check out the Testing Garden Assumptions Series  where I take a look at garden Methods, Practices and Products to see if they are supported by science. The videos that are published the first Friday of the month have taken an in depth look at the materials we used today and they are supported.  “The Truth about Garden Remedies” by Jeff Gillman (2008) p. 41  Testing Garden Assumptions Series Playlist: https://www.youtube.com/playlist?list…
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