Planting Soil Blocks

April may be my busiest time of year, and I am very late in my posting this month. One of those busy things is transplanting dozens of seed flats full of young plants. It’s now time for many of them to go outside.

My experience with Soil Blocks has been really great. I get very good results and avoid using pots whenever possible, but nothing ever goes as planned. This year I’ve noticed two problems. The first was I used a different brand of worm castings in a few trays. These plants struggled and it looked to me like there was a phosphorus deficiency and I found it necessary to supplement them with some liquid fertilizer to keep them going. The other problem I noticed was that for some of my plants I believe I started them a little too early in the season and by the time they were transplanted some of the lower leaves started to yellow, also indicative of a nutrient deficiency.

traysPictured here are many of my Brassica transplants: three varieties of kale, two broccoli types and a purple cauliflower. These seven trays had been growing in my basement for at least four weeks prior. A week before my transplant date I moved the young plants outside into the hoop house so that they can begin to feel what the outside world is like. This is called hardening-off.

The next step is to prepare the transplanting bed. I first used a hula-hoe or scuffle-hoe to quickly mop up any weeds that had germinated and pull any larger weeds. I then added some humic acid, kelp meal and some rock dust made of crushed basalt. Mix this into the top two or three inches, then rake the bed out flat.

Now I determine spacing, information usually given on the seed packet. I’ve learned that not all seed packet information is the same. I usually also look through a reference book or two and search the internet as well. Your experiences and individual soil conditions will also suggest differences. I do most of this look up during the winter months when I am stuck indoors and document them on my calender.

bedrowFor transplanting, the first step is to determine the plant spacing. Plant spacing is easy, it’s the distance recommended between each plant. Don’t confuse that with seed spacing, you want the final spacing between plants after thinning. I review, but usually ignore the row spacing. Row spacing is how many feet between growing rows if you’re farming, or as many gardeners do scaled-down farming. Pre-industrial gardening is a nearly forgotten art. Most gardeners base their knowledge on the experience of farming and scale that downwards into the garden space. The spacing used for farming is very inefficient and was born out of the need to accommodate a tractor.

For my Brassica’s, I started at the end of the four foot wide bed and measured out two rows for the broccoli and cauliflower, and three rows for the Kale. Please note that the distance between my rows is the plant spacing, NOT the row spacing. You can even go a little smaller if you stagger the transplants in each row. Another thing I’ve learned is to be sure and think about how your going to weed later in the season and to always leave enough room for your favorite weeding tool. I normally space my bed rows no less than 6-8 inches apart. Then I take a stick and carefully draw the rows down the length of the bed to mark them.

Now I extend the measuring tape down the length of the bed and fix it there. Using a hand hoe I quickly dig transplanting holes using the measuring tape to guide the spacing. When you have more than one row in the bed, I alternate the transplant holes. For example, with my kale I used 12 inch spacing and I dug holes down the first row on the foot markers (1, 2, 3, …). The second row I offset the holes by 6 inches (1.5, 2.5, 3.5, …), and for the third row I went back to the foot markers (1, 2, 3, …). This actually put each plant at about 13.5 inches apart. This gives you whats called BED SPACING. In the same space using traditional rows I would have only achieved two rows, not three, and I just increased my yield by 33%.

sbOnce all the holes are created, I decided to insert a small handful of high quality worm castings into each hole and mix it up by hand a little. Then I carefully lowered each block into its new home, but haven’t buried them just yet.

Since this blog is about Biological Gardening, how could I leave that out. I now mix in some beneficial bacteria with several gallons of water and use a watering can to wet each block well. After this I carefully bury each plant up to its cotyledons. The cotyledons were those first two seed leaves that formed after germination.

Since I did this work a few weeks ago now, I can also report how they are doing: The plants with the bad worm castings, have recovered and are now growing well, although they are still behind the others. The plants that were started a little too early are still alive and growing but they did struggle to get through a few light frost. The plants that were started indoors at the appropriate time, are doing amazingly well and are bright, green and happy. Despite the differences, of the 224 brassica plants featured here I haven’t lost a single one.

Why would the plants I started only one or two weeks earlier be struggling from a few light frosts when the others are so nice? Their brix was low because the block didn’t have enough nutrition to support that extra growth time. We can discuss this more in the fall, but a high brix plant is not phased by a little frost, as the extra sugar/nutrition lowers the freezing point of the plant.

Cheers,

~Sean

pH part II

In the first part of this article, I presented what the conventional approach to pH is, what it’s accused of doing, some ideas on how pH actually works in the soil and should have impressed upon you the notion that pH is hardly what it’s made out to be. There’s a claim that “good plant growth” can’t be assured unless you fix your pH, but I counter that notion and state that this assurance can only come from appropriate soil mineral nutrition.

pH is not a cause… it is an effect.

It is the reflection of the the soil makeup. In our case we want nutrient rich crops growing in fertile soil with the most happy pH of 6.4. This would afford maximum nutrient availability to the plants. If however your pH is too high or too low, the pH is not the cause of poor plant health rather it is sign, a message to you about the state of your soil mineral balance and biological activity. It’s also not the end of your gardening career if you can’t achieve the perfect reading, many native soils can be difficult to impossible to move very far. If you can’t get your pH into the ideal range experiments have shown that if a plant’s roots have access to adequate nutrients and there is no toxicity then pH makes little difference. Therein lies the crux of the problem, availability of nutrients is the limiting factor, not pH. A strongly acid or alkaline soil may be a sign that soil nutrition is in bad shape, but that can be mitigated by excellent biology.

vinesCalcium lime is not the only material that can raise the pH either, so can magnesium, sodium, carbon and potassium. Likewise sulfur is not the only mineral that will lower the pH, so will phosphorous and chlorine. On your typical farm, the heavy use of salt fertilizers creates a situation of rising pH levels, where calcium is not then being applied, resulting in a calcium deficient soil, followed by cascading nutrient failures and greater and greater problems. In your garden things could be different, or very similar, with over application of dolomite lime creating a magnesium problem, or an over application of compost/manure creating phosphorus or potassium imbalance achieving the same situation. Poor nutrient availability to the plant leads to poor plant health leads to disease and insect attack and a low quality nutrient poor product.

In my own garden space I had just this case. A slightly high pH with a soil mineral matrix that included naturally excessive magnesium and potassium, little calcium and several years of over zealous applications of manure and compost that intensified the imbalance. It was the perfect situation for induced plant stress, low quality vegetables and rampant weed problems… much to my dismay. Had I followed the conventional thinking, organic or not, a little bit of sulfur would have been applied along with more compost. Net result would have been an ever worsening change in the soil, including increasing soil compaction and no improvement whatsoever to produce quality.

What about the idea that certain plants prefer a soil within a particular pH range? For example blue berries are thought to prefer an acid soil of 5.5 to 6.5, alfalfa from 6.5-7.5 and corn and wheat from 6.5-7.0. Studies in plant nutrition and available calcium have shown the truth of the matter (Soil Acidity as Calcium (Fertility) Deficiency Albrecht), when there is sufficient calcium for good growth then pH as low as 4.5 can grow a great crop. And since low pH soils are usually limed with calcium it erroneously leads one to think that pH makes a difference. Even the nitrogen fixing abilities of certain soil bacteria on legumes only works effectively when there is sufficient available calcium in the soil regardless of the pH.

Interestingly there is an alternative way to understand pH that makes a lot of sense. Recall from the last article I introduced the idea of positively charged ions called cations, and negatively charged ions called anions. What’s the importance of this? It’s that pH is a measurement of electrical resistance in the soil. Thus a pH reading of 7 means that there is an equal amount of resistance between the cation and anion charges. A high pH indicates there is too much electrical resistance in the soil, causing a restriction in energy-nutrient flow to the plant, while a low pH indicates that there is too little resistance causing an overload of energy-nutrient flow. Keep this idea in mind as in the future we will discuss this in more detail and how we can use electrical conductivity to monitor and improve upon plant nutrient uptake.

So instead of working to adjust your pH, it’s more essential to manage the factors that construct the soil pH. A very fertile soil for high nutrient and energy production is a living biological system and must must be carefully balanced for the needs of the soil microorganism via an equilibrium of pH, soil minerals, energy, physical conditions and organic substances. Without this balance, the potential for plant nutrition and soil building erodes.

Remember then, that pH is a consequence of soil nutrient and biological interactions, it is not a cause of anything. pH can however be a useful gauge for you to monitor how various nutrients and other substances you apply are interacting with your soil. It is not however to be used to determine what nutrient, mineral or compound to apply to the soil. That should only be done after you have carefully reviewed all the factors that contribute to excellent soil fertility.

~Sean

pH part I

If you’ve been following along with me you should well know by now my interest in growing high quality nutrient dense foods. Unfortunately food like that is a rare exception, both in the grocery store and at the farmers market. Before we can begin to discuss what that really means and how to achieve it, there are a number of ideas that all gardeners are taught that need some amending. I must first bring up the problem of pH.

Simply put, pH measures the concentration of hydrogen ions, where a low pH is called acidic and a high pH is called alkaline. A quick search on the internet for pH gave me a random University Extension Office document that says “Soil pH is important because it influences several soil factors affecting plant growth”. It goes on to inform the reader that it can do many bad things like preventing bacterial release of nitrogen, soilit can cause nutrient leaching or restricts availability of nutrients to plants, creates heavy metal toxicity and makes clay soil hard to cultivate. It goes on to say that “a pH determination will tell whether your soil will produce good plant growth or whether it will need to be treated to adjust the pH level.” Most importantly it gives you a solution to this insidious problem: add lime if your pH is below 6.5 and sulfur if it’s higher than 7. And if your one of those lucky fellows who’s soil is in the sweet spot of 6.5 to 7.0 then you don’t have to do anything at all. Sounds like pH is very important and according to this we certainly couldn’t have good plant growth without it.

That is the conventional approach to pH and anyone that knows me well can picture me cringing right now. The issue I have with this is that pH is treated like it has meaning unto itself. The soil is considered secondary to the pH. If this recommendation were followed up by your typical NPK soil test lab and their garden soil correction plan of applying composted chicken manure, it’s quite clear that attention is only indirectly given to plant nutrition. Following these recommendations is a shot in the dark. If you’re lucky your soil conditions may actually improve until you do the same thing again next year, but for many gardeners it can do precious little to improve “good plant growth” and can actually make things worse.

First we need to talk a little about what pH is. It stands for “power of Hydrogen”. pH is a scale ranging from extreme acidity starting from a score of 1, to extreme alkalinity and a maximum score of 14,  with 7 being the happy middle, the point of perfect balance. Water (H2O) separates easily into two ions with one of hydrogen (H+) and the other called hydroxyl (OH-). When these ions are in a one-to-one ratio you have a balanced pH of 7. If there are more hydroxyl ions (OH-) than hydrogen (H+) then the pH will be higher than 7, and if there are more hydrogen (H+) ions then the pH will be lower than 7. Thus, pH is a measure of hydrogen (H+) ions in solution.

This is however too simple to be useful. Hydrogen ions only cause soil acidity as measured by a standard test when they are in water, think of the water based test kits you see in the stores. In the soil, most hydrogen ions
beansare loosely attached to the soil particles along with many other positively charged ions called cations. These cations are there because of attraction to the negative charged particles, called anions. Anyways, these soil born hydrogen ions may not even contribute to soil pH unless the soil conditions change. Another interesting point is that as plants and microorganisms develop they will pull the plant nutrient ions, the cations, away from the soil particles and swap them out with additional hydrogen ions, thus causing the pH to drop during the growing season.

Materials you might consider adding to the soil to raise the pH are things considered to be alkaline such as calcium lime. However, this is relative to what might already be in the soil. For example calcium applied to a high magnesium soil may actually lower the soil pH. The same goes for acids, it’s relative. The  application of an acidic substance to the soil can actually further increase your pH, the wrong direction. Further, your soil could be desperately short in calcium, an essential plant nutrient, and have a high pH. In that case following the standard pH amendment procedure of not applying calcium lime would keep your soil in a very poor state and the healthiest weed growth yet.

Lastly, those that worry about pH will also state that too low a pH can release too much nutrients causing heavy metal toxicity or too high a pH can cause the locking down of the nutrients so they’re not available to the plants. This may be true in a sterile laboratory, but in a biologically active soil it’s quite different. Biological compounds interact differently than non-biologic compounds. For example, a high pH soil can be induced to release nutrients when organic humates, molasses and biochelates are used. One more thing, if you measure your soil pH on a weekly basis you will see it change throughout the year, this is at least partially due to increasing or decreasing amounts of microorganism activity.

Thus your soil pH score is the result of complex chemical, physical and biological interactions and doesn’t give any clues about what might actually be in your soil. Taking actions based only on this number is the surest way to limit the nutrient potential of your vegetables and induce plant stress. A pH reading however isn’t completely useless, in part II to this article I will elaborate further on this topic and how it can be a useful tool to growing great foods.

~Sean

Soil Blocks: the Building Blocks of Life

Within the first few days of seed germination the maximum yield for your vegetable plant has already been determined. From that point on any and all types of stress that the plant sustains has a direct impact upon your harvest, be it from the weather, nutrients, water, chickens, children, insects, cloudy days, etc. Thus any effort you make to increase your yield in reality is an effort made to decrease your loss of yield. As garden manager, your role then is to identify ways to reduce plant stress at every possible stage to ensure a bounteous crop of nutrient rich food.

blockerThe place to start your plant stress reduction strategies is during seeding, actually it starts with seed selection but that’s for another time. I quickly learned during my first year of indoor seed starting that there was a trick to accomplishing this successfully. First, it didn’t take me long to realized that I was going to have to replace all my black plastic seedling flats every single year, they sure make those things cheap. It also just pains me to have to buy the same thing over and over again year after year, but what other options were available? A little bit of online research revealed to me another method and no more plastic cells and pots. Instead, the pot can be made of the soil itself, soil blocks!

With soil blocks, my young plants grew more vigorously and were highly resistant to the stress of transplant shock. Also, the seedling roots no longer spiraled out of control at the bottom of the cell or pot, but instead upon hitting the outside air the roots will check their own growth and then shoot off again after transplanting. Additionally, losses due to transplant shock were very rare with almost 100% transplant success. There are however a few new concerns. First, you have to be more careful with watering, the extra soil surface area dry’s out a little faster, but that’s easily managed. The other thing is that it’s more time consuming to build the blocks, but this is one area you can have a big impact on plant stress and its worth the extra time, besides its still winter and it gives me something enjoyable to do.

If you want to try soil blocks here is my method, there are many variations so don’t think this is the only way:

  1. soilblocksPick up the soil blocker of your choice off the internet, you can even find directions for making your own. I purchased a 4-cell two inch block maker and it will last me a lifetime of use.
  2. Pick up several higher quality leak proof seedling flats, still black plastic but reusable every year. Naturally they cost a little more, but the price makes up for itself after only one year. Whatever trays you use its important that they do not leak. All the trays I bought from the big box store’s were junk.
  3. Pick up an equal number of black plastic flats that are perforated, or just melt some extra holes into the ones you were going to throw away from last year. The flats I found at my local seed store were exactly that.
  4. Insert the perforated flat into the leek proof flat. When you want to water your blocks gently pull the top tray out, add water to the bottom tray and reinsert the top tray. Always bottom water your soil blocks.
  5. Make your block mixture. There is a trick to this, if you use the wrong materials, not enough water, or too much water then your blocks may not work out. I use about 80% soil less seed starting mixture, 10% high quality worm castings, 5% rock dust, 5% kelp meal and a bacteria/fungal biological inoculation. Mix with water to the right consistency and start making your blocks.
  6. Space the blocks on your trays so there is at least a 1/2 inch of space between them.
  7. Drop your seed of choice into the small hole at the top. Then for most seeds I take a pinch of the soil less mixture and cover the seed, followed with a squirt from the spray bottle to dampen it.
  8. Cover with a clear plastic dome to create a moist environment and wait for germination.
  9. Drink a nice glass of wine to celebrate your hard work and reduce your own stress.

~Sean