Post-Harvest Soil Fertility for Trees & Vines

Most growers know it's a good idea to add water and nutrients after harvest. Vines and trees are very similar, so are soil practices. As grapes enter dormancy, crop potential for the next growing season has begun.

  • Less water applied close to harvest is common. Replenishing soil moisture is essential

  • In-season tissue analysis determines post-harvest nutritional needs

  • It's time to help the vines build and store carbohydrates, sugars and nitrogen. Add a carbon source with N fertilizers

  • Add microbiology with Black Diamond VermiCompost Liquid Biological Extract - microbes enhance fertilizer performance and are fundamental for productive soil

Living soil is productive soil. Plants have amazing communication skills. The vast majority of soil microbes have yet to be identified, but what we do know is when diversity exists, the entire plant, including fruit, above and below ground, benefit.

[Excerpt] Extensive communication occurs between plants and microorganisms during different stages of plant development in which signaling molecules from the two partners play an important role. Fungal and bacterial species are able to detect the plant host and initiate their colonization strategies in the rhizosphere by producing plant growth-regulating substances such as auxins or cytokinins. On the other hand, plants are able to recognize microbe-derived compounds and adjust their defense and growth responses according to the type of microorganism encountered.

This complex and fascinating conversation that takes place between soil microbiology and a plant's root system is part of the ongoing soil science we follow. Minerals and microbes must both be present for the cycle to be effective.  The entire article can be found here. (

By adding teas and/or extracts:

  • nutrients stored in the bodies of the microbial life are not lost through irrigation or abundant rainfall

  • hair-thin fungal hyphae, or tentacles, wrap around soil particles in their search for food, forming aggregates for improved soil texture

  • both the fungi and soluble organic matter are held in the soil

  • bacteria release a sticky mucous that enable them to cling to solid particles of mineral and organic matter, ensuring they too remain in the soil and, like the fungi, aid in the formation of aggregates.

Properly made compost teas and extracts, when using vermicompost as the base, adds a plethora of unique soluble plant nutrients and growth compounds, a diverse microbial population, and organic matter that provide an ongoing supply of nutrients. The plant receives a consistent and reliable food source when bacteria and fungi feed on the organic matter. This below ground surface microbial activity releases some of the nutrients to the soil and retains others for their own energy and reproduction. When nematodes and protozoa in turn feed upon them, the nutrients stored in the bacterial and fungal cell walls are released to the soil in a highly soluble plant available form. When we feed the soil, the soil feeds nutrients to the plant.

You can learn the differences between aerated compost teas and extracts here

Since you have read this far...(thank you!)...I hope you will take advantage of the offer that ends in October. It's a substantial discount, and we are confident that your vines will wake up next year with energy, vigor and a stronger immune system. The details of the offer can be found on the home page.

Cabbage increased by 23%

I'm thrilled when our friends and customers put Black Diamond VermiCompost to the test! I had no clue about this one until it was over and done and report written. Thank you Erica!

Erica Reinheimer

OrganiCalc Soil Analyst at


This spring I tried a no-till system for the second time. Twenty five years earlier I covered a portion of our rainy Hillsboro, Oregon garden with black plastic, hoping it would be drier in the spring and allow an earlier planting. The plastic was in place about 5 months. It was partially successful – the soil was easy to fork, as there were no live plants in it. It was very wet. It had a musty smell to it I didn’t like.

In 2017 I revisited a tarped no-till method. This trial was  in Arroyo Grande, California, where we got 30” of rain in the winter of  2016-2017. The tarp I used was stiff enough for airspaces beneath it, unlike the black plastic. The tarp wasn’t in place for very long; about 6 weeks was all it took to kill the weeds. I used the worst part of the garden for this experiment, an area which never amounted to much. I had done comparative soil tests and know the mineral profile of this section is as good as the more productive parts of the garden. I took the failures to be because of intense root competition from neighboring trees.

When I pulled back the tarp I was amazed to see a proliferation of earthworms. They are otherwise very rare in my garden. I scattered quite a bit of feathermeal on the surface, along with the slightest bit of borax possible, and a sprinkling of gypsum for sulfur. These anions leach easily, and often have to be replaced for every crop. The other minerals, the cations, were already in place after years of soil testing and mineralizing. 

I had some extra cabbage plants, so I began transplanting them with a trowel; with just the minimum digging necessary to get the plants into the ground. The soil smelled good. As I had a bit of purchased Black Diamond vermicompost around, I dug one or two handfuls under the transplants in the top row before transplanting. I was fortunate to get the Black Diamond vermicompost; all vermicompost is not the same. Black Diamond has been chosen for the vermicompost trials at Ohio State (and small quantities are available by mail). This is a very tough test of the vermicompost; the bottom row of every bed does better than the top row.

I labeled the rows, and pretty much left them on their own until harvest. The rows got drip irrigation added about 40 days after transplanting (the ground remained quite wet after transplanting). They got weeded and mulched. Maybe kelp was foliar fed a couple times. That spring we were traveling a lot, and the garden didn’t get much care.

When I went to harvest a cabbage, the most mature and best looking one came out of the top row, the row with vermicompost. We took it to the 3 day Live Oak Music Festival where the temperatures were in the 90s. The cabbage was still very good on the third day, without any refrigeration. Quite a surprise. The top row matured earlier than the bottom row. The top (vermicompost) row yielded more.

Here are photos of the paired cabbages. The cabbages with the vermicompost are on the right. All the cabbages are a bit over-mature, though they still taste good.

Here is a comparison of the weights of the paired cabbages:

Left cabbage 3.5 lbs; right cabbage 4.5 lbs

Left cabbage 3.5 lbs; right cabbage 4.5 lbs


The tarping/no-till method worked extremely well. I’d pretty much abandoned this part of the garden due to low yields. I’d never gotten anything like this out of this area before. When I went to plant the next crop, my 12” fork went into the soil fairly easily, then I gently rocked the fork without turning the soil. This is a vast improvement over the 5” penetration earlier. There aren’t as many roots in this area as I had thought. Maybe the problem with this bed was compaction. The no-till method seems to help compaction more than rototilling.

I was surprised how effective mixing vermicompost below transplants is. I wonder if other crops might respond even more to vermicompost. Brassicas do not form mycorrhizal associations, unlike most plants; and vermicompost is an excellent source of diverse microorganisms.

 I have used this technique for some time, but this was the first time I quantified it. The cabbages with the vermicompost matured earlier and were larger.

I'd like to acknowledge a loyal customer

When things happen that make people smile and feel good about their hard work and passion, it makes me feel good too about our hard work and passion for healthy soil. So I'd like to share their story. Their new tasting room is now open too! Right off Hwy 101 in Paso Robles, just outside of Tin City. Be sure to stop in soon! 

Black Diamond VermiCompost Tea - the sole product in a successful soil fertility program

It is autumn and your trees deserve special attention now.

Our offer is simple:


Our friend, and experienced arborist, Kevin Stitt, has worked with us for several years now. Some of the oak trees on our property would have been fire wood by now if it wasn't for Kevin. Others we thought would surely not make it through the drought, are now thriving.

When I asked Kevin recently what he felt was important to consider at this time of year, he thoughtfully replied: "We were blessed with a decent amount of rain last winter, even though alot of it came at once and did more harm than good, in some cases. There was lots of fruit and nut production too. Follow through is essential and NOW is the time." So I asked Kevin if he would elaborate in a short article. I have included it below. We both hope you will take Kevin's advice. If only once you could see the smile on his face when he looks at the oaks he treated for us, only 2 times, you would understand...thank you Kevin!

Is the health of your tree related to its soil?

by Kevin Stitt

Have you ever thought about it?

Obviously, the individual plant genetics...basically the plants abilities to adapt various weather conditions, determines the plant’s survival zones.

We love to, given the opportunity, and being creatures of comfort, simply move indoors to a AC/heated vehicle or building  to keep cool or warm. Trees, on the other hand, must remain in place, in unbearable heat or freezing temperatures. All they have to hang onto is every inch of soil directly around their live "root zone."

While we cannot control the weather, we can assist the soil life in the plant root zone. Field trials and my personal experience bear witness to increased growth, restorative plant health and reduced re-plants! For the tree, in your landscape, the soil surrounding its base is everything!

Get to the root of the matter. Microscopic soil life lives around the roots, some attached to the root -- all working under a plant’s food release command, to change soil pH immediately around the root in favor of a plant’s seasonal uptake needs.  Soil microbes have the digestive enzymes that plants don’t have. Soil microbes store fertilizer inside their tiny bodies. A plant releases food through its roots into the soil to arouse a predator/prey reaction that releases the stored fertilizer on time and in the amounts plant needs.

Crazy as it sounds, the microscopic life in the top six to eight inches of healthy soil, outnumber what we are able to see above ground. Water passing through those 6-8 inches of live soil is purified. Our freshwater supply depends on microscopic soil life in plant root zones.

Soil bacteria is like glue, and when combined with sand, silt, clay and organic matter, creates soil aggregates. Water retention increases and pore spaces create more room for root growth.

Many things in nature that appear to be simple are quite complex. The more we learn about the ecosystem around us, the more aware we become of the detrimental effects excess fertilizers, pesticides, herbicides and fungicides have on this amazing system, and on human and animal health.

So when is a good time to treat the deep root zone of your trees?  Now! Be proactive! Increase your soil microbe population!  Disturbances, caused by weather or human activity, has caused them to diminish. The process of fruit production itself through the season has used up much of the tree's energy. This energy must be replenished for next year's production.  While your trees are resting above ground, there should be alot of activity below ground during the winter getting ready for Spring and a new season of nutritious food production. Why wait till your tree can not get what needs from the soil and tree has disease or insect issues. Let's talk tree health soon.

A Special Thank You to a Special Friend

I have been thinking lately about how many special people I have met since starting this incredible vermicomposting journey in 2009. Dawn is just one of these warm and loving people. Her work with horses is may already know about her. But when she planted a few trees (as shade for her beloved horses) and wrote this blog post, all I could do was well up with happy tears. Read her post here, and be sure to look around this will soon learn how special she really is. Thank you Dawn!

Are all worm castings created equal?

Yes, and no. Worms transform whatever they consume to a very different material. However, the food they start with plays an important role in the value and quality of the final product. At Black Diamond VermiCompost, dairy manure is "hot" composted prior to feeding to the worms. This stage kills pathogens and weed seeds and is closely monitored and adjusted to maintain optimum temperatures. The worms are fed this pre-treated food and thrive on the bacteria, fungi and other decomposers that are generated through the composting process. A few weeks later, vermicompost is harvested. The final product, Black Diamond VermiCompost,  is a very mature and stable material, promoting soil health and vibrant, strong, productive plants and trees. It will not burn and is safe for the most sensitive plants. Lab results are impressive. The worms are doing their job! We do our part to keep them well fed, warm and moist in an environment as close to nature as possible. 


Photo by Cristy Christie

Photo by Cristy Christie


Above ground, many trees, shrubs and plants are dormant now, but below ground, in the root zone and surrounding areas, there's a party going on! With the welcomed rains on the Central Coast and the warmer-than-usual winter weather (or maybe not so unusual!), the soil food web, including micro-organisms, micro and macro arthropods, and earthworms...if you're lucky enough to have some...are alive and active. If there IS, in fact, a soil food web there to begin with. It could be a good time to add VermiCompost to the garden beds, around trees and shrubs and top with mulch, (we use a lot of straw - it's a good source of carbon) to keep them warm and happy, in case we get a frosty snap. Microbes love moisture, and by adding organic matter and microbes now, they have the opportunity to multiply and thrive, getting ready for your spring plantings. 

If you weren't real pleased with last year's crop, perhaps a soil test is in order. Give me a call, and with a few questions, I'll direct you to the right place for a simple, inexpensive soil test. It will provide you with information regarding the amount of organic matter in your soil, what minerals are present and in what quantities, along with the capacity of your soil to hold them. When you receive your test results, we'll make suggestions to put your soil in balance and you'll be on your way to a rewarding experience of nutrient dense food that make your taste buds dance!

Remember, if healthy is not in your soil, it's not in your food. If healthy isn't in your food, it's not in your body. 

-Cristy, Black Diamond VermiCompost

The Drought & Our Native Trees

Hopefully the drought is coming to an end in Central California. For our native oak tree population, as well as other deciduous trees, we offer the following information:

The above ground level effects of drought on plants can be easily seen. They include wilting, leaf scorch, some defoliation, stunted growth, branch die-back, and possible death of the plant. The below ground level soil life affected by drought is less obvious and can be unknown. 

As soils become dry, the fine feeder roots in the upper soil surface will begin to die if soils remain dry, thus putting the root system out of balance with the amount of foliage found above ground. When rain does return, the plant may not be able to take full advantage of this much-needed water because of its reduced root mass and reduced soil biology.

Soil biology is vital to rapid healthy root growth. Soil microbial communities (soil foodweb) improves water holding capacity by binding soil particles together forming aggregates. They also aid roots by keeping nutrients near root zones and compete with disease-causing microbes. They filter and degrade pollutants as water flows through soil, break down complex carbons. Mycorrhizae fungi assist in plant roots development. 

Beneficial soil microbes are found most concentrated in properly made compost.  Quality control in the balancing of energy (carbon, C) and nutrients (primarily nitrogen, N) is the beginning point. Then having adequate moisture and sufficient oxygen to support an aerobic environment is critical.

-Cristy, Black Diamond VermiCompost