Monitor soil temperatures before planting

Soil temperatures have been cool enough during April that it has slowed down plant growth. My winter rye cover crop looks to be a week behind last year at this date and last year was later than normal as well. So that means we’re really behind. The apple tree buds have finally, slowly opened.

This may be the year to monitor soil temperatures more closely than usual if this cooling trend continues.

Some vegetable crop seeds can be sown into cold soil and do quite well under those conditions while others will not germinate or grow at all. There are certain minimum temperatures that seeds need in order to germinate. Seeds languishing in cold soil will be damaged or more likely, rot in place before they sprout.

For example, at 35 F you can expect spinach, onions, parsnips and lettuce to germinate. We’re well past that point by now.

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Although not as durable, a kitchen thermometer makes an adequate replacement for a soil thermometer

Beets, cabbage, cauliflower, Swiss chard, radishes, turnips, peas, and broccoli will all germinate at 40 F. Even though they are not technically seeds, seed potatoes will begin to grow at that temperature too.

Sweet corn requires the soil temperature to be at least 50 F. If they are pinched for time, some farmers will plant corn at lower soil temperatures but they always use seeds treated with fungicide to keep them from rotting in the soil.

A minimum soil temperature of 60 F is needed for warm weather crops like beans, cucumbers,melons,pumpkins and squash seeds to sprout.

Keep in mind that these are minimum required temperatures. Optimum germination temperatures may be five, ten or even twenty degrees higher in some cases.

You may have noticed that I didn’t include many common vegetables like peppers or tomatoes in these lists. That’s because in our growing area, those plants are generally grown as started transplants, not from seeds planted directly into the ground.

Bob

Reproduce forest floor soil for new trees

Spring is the best time of year to plant trees. During the winter the dormant buds and roots are in a kind of holding pattern until the right growing conditions happen in the spring. Then they have the entire growing season to establish themselves before next winter.

No doubt you’re aware of the requirements for a proper sized planting hole and the need to water the young tree after planting. Proper planting depth is also very important. I’ve mentioned in previous posts how important it is to remove the wrapping from the root ball, even though it can be a hassle.

I always set aside any sod and never use it to back-fill the planting. Actually, I don’t use the topsoil to back-fill either. I just use the subsoil from the hole for back-fill and save the topsoil for the very top of the hole. That way the original soil profile is maintained.

After I’ve taken great pains to get the tree into the ground, there’s one more thing I like to do to and that is to create an artificial forest floor covering.  It’s something I’ve been doing for decades and I like the results.

It’s really a way of mulching that small trees seem to respond to. I first apply a thin layer of partially decomposed wood chips around the newly planted tree, over the topsoil,  maybe a couple of inches deep. Then I cover that with a layer of chopped leaves. Chopping the leaves prevents them from matting down which can slow down rain water penetration into the soil.

The layering combination of subsoil in the hole, with topsoil over that then covered with the chips and leaves mimics the soil conditions of a forest. I don’t mix the layers, I let the soil microbes do their thing. Eventually as the mulch decomposes, humic acid and related compounds are formed providing an environment for a wide variety of beneficial soil microbes. All of that allows the tree to adapt to its new home and grow to its full potential.

The chopped leaves and wood chips here are applied about four feet in diameter.

Not everyone will want to fuss with their trees like this and some will say it’s overkill and I certainly wouldn’t expect a landscaper to do it. but it’s something I’ve found to work for me.

Bob

Fixing seeding mix that won’t absorb water

We’re sowing our seeds right now for growing transplants that we’ll plant out in the garden. It takes some work, but you can save quite a bit of money growing your own transplants.

Another huge advantage that may be even more important is being able to grow the varieties you want rather than relying on what the garden center grows. They usually chooses varieties that are the easiest to grow, not necessarily the tastiest. That makes sense in their business model. People who have success with their plants are more likely to return the following season.

Starting your own seeds is not without its problems. Some of them you can plan ahead for and minimize, others pop up out of the blue.

We’ve had a great start with our seeds this spring, the cabbages and related cool weather crops are up and growing well. We were using the last of last year’s seed starting mix but ran out. The local hardware store had plenty of bags of mix in stock so we bought a small bag so we could keep working. It felt a little light and fluffy when I carried it, that should have been a warning sign but I was in a hurry.

When we got it home and started working with it, we found that it would not absorb water. Even after sitting  in water overnight, not a drop was absorbed by the mix! It was a “hydrophobic” mix; it was repelling water. That happens whenever potting soils dry out too much. Usually manufacturers make sure a minimum amount of moisture is present to keep that from happening or they include a small amount of  a”hydrophillic” ingredient in the mix to help it absorb water.

The container on the left has absorbed water normally. The one on the right is hydrophobic.

One explanation is we grabbed one of last year’s bags of soil that had completely dried out while in storage. But who knows?

To avoid this in the first place, always make note of how heavy the bags are compared to one another. Mixes are sold by volume, not weight so you don’t have to worry about wasting money on buying water. Pick the one that feels a little heavier because it is more likely to have the proper moisture ratio.

If you do happen to pick a bad one, like me, you can still fix it by applying small amount of surfactant. Even professional greenhouse have this problem from time to time. They use specially formulated surfactants that are not available to the general public but dish washing detergent will work just as well.

Here’s the recipe: dissolve one teaspoon (not tablespoon) of liquid detergent to one pint of water. Use the cheapest off-brand detergent you can find, there’s a practical reason for it. The name brands like Joy, Dawn or Palmolive make too many suds for this purpose. I have a bottle of off-brand detergent left over from several bottles I picked up many years ago when Farmer Jack went out of business. How long ago was that?

Place your solution in a spray bottle and spray it on the surface of your mix, that should give you enough surfactant to allow the water to soak in.

Sometimes the soil in a container will dry out and become hydrophobic even when a plant is growing is growing in it. When that happens, the plant will quickly die from lack of water. Your surfactant spray will fix that situation too. Just spritz a light spray on the top of the soil. It will help water penetrate but won’t harm the plant.

Bob

Almost no-till potatoes

This year I’ve decided to try a minor experiment with my potatoes. I guess you might call it a kind of no-till planting.

There are a couple of reasons I thought it might work well. First, the spot where they’re going was recently an area where some of my older chickens were penned in. I purposely kept them confined to a relatively small area to help clear it from weeds. They did a great job eliminating all of the existing weeds and keeping new ones from getting a foothold. Chickens enjoy grazing on fresh green plants and those wild greens provide plenty of vitamins.

Even though they are small, chickens can disturb a lot of soil in a short period of time. That makes them destructive if they get loose into a flower garden or other valuable spot and start scratching. Believe me, I had plenty of experience shooing chickens out of  flower gardens. It’s that relentless scratching that makes them such good helpers in the garden before planting time.

The area where my no-till potatoes are going there were no visible weeds. Under the surface however, there were thousands of recently germinated seedlings ready to pop up into the sunlight. Instead of using my rototiller, I used my sharpened swan hoe to skim along top half inch or so. I was able to cut off the weed seedlings before they had a chance to get started.

The theory is that while roto-tilling will destroy young weeds, at the same time it also drags up new seeds to the soil surface where they will germinate and grow. Shallow hoeing will kill weeds but not drag up new seeds. That Sounds like a good idea but there are plenty of dormant weed seeds waiting to take the place of their lost cousins. But over time, if done consistently, you can eventually reduce the number of viable seeds.

Back to my potato patch.

The second reason why I feel my quasi-no-till will work is because the soil is a sandy loam that really doesn’t need tilling to provide a good seed bed. If it was a finer textured soil with more clay content, I would probably not plant them without tilling.

Instead of using a trowel or shovel to dig the planing holes, I got out my two-handled post hole digger. That way I was able stand straight up to do the digging and I got a great upper body workout to boot.

The holes are plus or minus a foot apart with the rows around 28 inches apart.  At that planting density, the potato plants should eventually grow together enough to shade the soil surface keeping it cool and shading out weed seedlings.

I made sure the rows were straight and the holes evenly spaced.

I know I’ll have to keep up with my hoeing through the season, “no-till” doesn’t mean “no-work”. I’ve seen many inexperienced gardeners learn that the hard way. Real no-till involves the use of herbicides to control weeds but I’ve never used herbicides in my vegetable garden and plan to keep it that way.

While hoeing will be my main method of weed control, I’ll mulch what I can.

Bob

Intensive soil improvement

A couple of posts ago I discussed a hands-off style of flower gardening that works sometimes in established gardens. In those cases the soil is usually in pretty good shape after having had plants growing in the same spot for many years. Not everyone is fortunate enough to have such a garden space.

Sometimes the soil in a potential garden spot requires a lot of work before it is fit to grow vigorous plants. Take for example the case of the typical yard of a newly constructed home. It’s not unusual for the builder to remove the existing topsoil and haul it away to be sold. Then, usually, soil excavated for the basement is spread over the new yard area leaving the new homeowner to struggle with the poor soil. The homeowner often ends up buying topsoil (most likely from a different housing project) to add to the yard.

New topsoil may be adequate to grow a lawn but not necessarily good enough to grow flower and vegetable plants. In that case, the laissez-faire method of gardening will have to be put on hold until the garden has built up fertility and the soil structure has improved. That may take years or decades without major help from the gardener.

There’s a way to drastically improve a garden spot so it can be in tip-top shape the first year. It’s a method called “double digging”. Double digging is not for the faint of heart. I did it one time many years ago for a problem area and I can tell you it’s a heck of a lot of work but the results were impressive.

I suggest starting with a small garden bed in case you run out of energy or patience before the project is done.

A sturdy garden fork is an essential tool for double digging and general garden work.
A sturdy garden fork is an essential tool for double digging and general garden work.

Start by digging a trench about a foot wide and the depth of of your shovel along the entire lenght of one side of your new bed. Pile the soil from the trench along side your excavated area. Then insert a garden fork into the soil of the bottom of the trench. Use the tines to break up that layer of dirt and incorporate some compost as deep as you can.

Dig another trench along your original trench, again over the entire length of that same side. Take the soil  that you remove from digging  your second trench and place it into your original excavation, right on top of the loose soil and compost. Once the second trench is done, dig another and another until you eventually reach the far side of the bed. Fill the final trench with the soil that you took out of your very first trench.

The final step is to spread more compost over the entire garden bed and deeply dig it in to the soil with your garden fork. If you plan to add fertilizer, now would be the time.

The soil will be fluffy and full of air-pockets so you’ll need to water the area a few times to help settle the soil before planting.

In some gardens, double digging seem like over-kill but in certain circumstances it’s the ideal way to build a garden bed.

Bob

 

 

 

Using wood ashes in the garden

If you enjoy regularly using your fireplace or wood stove, you know that a fair amount of wood ashes can be accumulated over a heating season. Under the right circumstances, those ashes can be an excellent fertilizer for your garden.

Wood ashes contain about ten percent potassium, one of the three major elements needed by plants to grow and survive. That is a relatively high percentage of potassium for a no-cost,naturally occurring material that is easily available. It doesn’t need to be mined from the ground, packed and shipped long distances to a garden center.

Many natural sources of potassium like greensand release their nutrients very slowly over a period of moths or years. Wood ash potassium is in a form that is very water soluble making it immediately available for plants to use. Because of this high solubility, potassium is quickly lost if the ashes are stored where it can be rained on. The rain water essentially washes away the potassium, so it’s important to store ashes in a dry area.

Calcium, at about sixty percent, is the other major constituent of ashes. It is in the form of calcium carbonate, the same compound that makes up agricultural limestone. When soil pH is too low, the soil chemistry changes to the point where the nutrients are no longer available to the plants. So farmers and gardeners add limestone to raise the pH to the optimum for plant growth.

Ashes contain trace amounts of micro-nutrients too. Those are essential nutrients that are needed for plant growth but only in tiny amounts compered to the three major nutrients of nitrogen, phosphorus and potassium.

Depending on soil conditions about thirty to one hundred pounds of limestone is commonly added to a thousand square feet of garden. However, only about three to ten pounds of wood ashes are required to do the same thing, about one-tenth the amount. Why is that so if wood ashes and limestone are both made of calcium carbonate? It’s because the particles of wood ashes are so small that the calcium is immediately  available while even finely ground limestone has to break down even further in order to work.

Wood ashes work so quickly to raise soil pH that there is a danger that the soil pH can quickly get too high and cause other problem for your plants. It’s always a good idea to check your garden’s soil pH to get an idea on how much wood ashes to apply.

Bob

 

Looking at basic soil test results

You’ve read it here in this blog, you’ve heard it from your neighbor, even your Aunt Bootsie told you to get a soil test for your garden.  I’ve always recommended using the soil testing lab at Michigan State University, it’s the “gold standard” of soil labs in Michigan. For most gardens a basic test will provide you with all the information you’ll need.

In past blogs I’ve described how to properly take a soil sample for testing and what to do with it once you’ve collected it, so we won’t discuss that today. Instead we’ll look at actual soil test results.

Once you’ve rounded up a bag of dirt, sent it to the lab along with your payment, the MSU soil lab will test your sample, processes the results and send you the test results either by email or by mail. That usually happens within ten days.

Let’s take a peek at an actual soil test readout I received last fall.

Results from a soil test
Results from a soil test

The first test result is the soil pH. pH describes how acid or how alkaline your soil is with “7” being neural. In this case the sample result is 7.6 which is somewhat alkaline. So right away we know we won’t have to add any lime to raise the soil pH since most garden plants grow best in a slightly acidic soil.

Next is the result for phosphorus, the “P” in NPK. The result came back at 58 ppm (parts per million) which, according to the graph is well in the optimum range.

Following P we see that is the potassium (K) is 67 ppm which we see is below optimum. Magnesium (Mg) at 202 ppm is above the optimum range.

Calcium(Ca), shown in the additional results section is 2443 ppm which helps to explain the relatively high soil pH reading since calcium will raise soil pH.

The next result is CEC (cation exchange capacity) this tells us how well the soil is able to retain soil nutrients. A reading of 14.1 tells us we can add fertilizer to this garden without having it leach out of the soil. Usually, soil types with a higher percentage of clay in their make-up have a higher CEC and therefore are inherently more fertile because of all the retained nutrients. Very sandy soils have low CEC values. It is very difficult to change the CEC of a soil. On the other hand, we can easily raise the NPK values by simply adding fertilizer.

Those cations (positive-charged ions) that are being described in the CEC reading are mostly K, Mg and Ca. There is a section in the readout providing the percentage of each of those. Phosphorus is not listed there because it exists in the soil as negatively charged anion (PO4 3-).

Nitrogen (N) is not tested for at MSU because soil nitrogen levels change with the temperature and other variables so you would never get an accurate reading.

We don’t have room here to discuss the soil science behind the results. Fortunately, the soil lab boils it all down to some simple recommendations at the bottom of the readout.

The nutrient needs are listed as actual pounds of each element per 1000 square feet. Since fertilizer is not sold as pure nitrogen, phosphorus or potassium, the precise amount of any type of fertilizer must be mathematically calculated. Back in the olden days when I was an MSU Extension Agent and the results were printed with a dot-matrix printer, I made those calculations by hand on hundreds of test results. Nowadays MSU has an online calculator that you can use to figure out how many pounds of fertilizer you would need to apply.

With the planting season rapidly approaching,I suggest you get your soil sample to the lab ASAP. Much like your income tax return; the sooner you send it in the sooner you’ll see your results.

Bob

 

 

 

Don’t till wet soil

Tilling a garden at the wrong time can be damaging for certain types of soil. That is why it’s good to know when to till. Tilling at the wrong time can be disastrous for a garden.

Gardeners make gardens in all types of soil: sand, loam, clay or, more often, a combination of two or more of these types. Short of hauling in new topsoil, there is nothing you can do to change soil type. Adding compost will vastly improve a soil’s ability to sustain plant growth but will not change the soil type.

Soil structure is different than soil type. Soil type refers to the size of the soil particles and the percentage of the different particles. Sandy soils have the largest particles while clay has the smallest, silt falls somewhere in between.

Soil structure refers to the arrangement of the sand, silt and clay particles in the soil. In soils with good structure , the soil particles are clumped together. That gives adequate space between the particles allowing water and air movement into the soil.  That provides the ideal environment for plant growth.

Tilling while the soil is too wet can destroy soil structure making it difficult for plant roots to grow.

Sandy soils are the most forgiving soil type. In a garden setting, sandy soils can be quite wet and still be tilled without doing much harm to the soil structure. On the other hand, loam or clay type soils are much more susceptible to soil structure damage caused by tilling wet soil.

There’s a simple test you can do right in the garden to help you decide when it’s time to till your individual garden. Scoop up a handful of soil and roll it into a ball. Lightly poke it with your finger. If it falls apart easily, it’s OK to till. If the ball holds together it is too wet to till. Let the garden dry out and try the test again another day.

Roll a handful of soil into a ball.
Roll a handful of soil into a ball.

This time of year, a good rain or strong thunderstorm can dump enough water onto a garden to set back your tilling plans a day or two so always check your soil moisture first.

Bob

Avoid damping off disease in seedlings by using boiling water

Growing your own transplants from seeds is a very satisfying experience and can save you money too. However it is not without it’s problems. Just about every gardener who has started plants from seed has a story to tell of watching a crop of seedlings just starting to make good growth then all of a sudden the plants shrivel at the soil line, fall over and finally die.

That is a symptom of a condition known as “damping off”. It also kills newly sprouting seeds under the soil giving the impression of a low germination percentage. The gardener gets the wrong impression that he’s planted a batch of bad seed when in reality it’s damping off.

Damping off is most commonly caused by a soil based fungus called Phythium, but Rhyzoctonia and other species of fungi can cause similar problems. Whatever the case, it is not curable.

It’s an insidious disorder. The seedlings can look sturdy and strong then suddenly,bam! overnight an entire tray of seedlings will be lost.

Most of the time you can avoid damping off by purchasing a fresh bag of sterilized soil-less seed starting mix. Sometimes however, even a new bag of starting mix can harbor the fungus, although that is pretty rare.

When Pythium shows up, it’s probably the gardener who contaminated the mix by using dirty tools, pots, or even the potting bench. All tools and containers need to be scrubbed clean with a detergent. To be doubly sure, the items can be dipped into a 10 percent solution of household bleach.

Although all plants can be infected, some species of plants are more susceptible to damping off than others. For example petunias are prone to the infection.

Pour the boiling water evenly over the whole surface.
Pour the boiling water evenly over the whole surface.

Whenever I start a batch of expensive or hard to find seeds and don’t want to take any chances of losing those precious seedlings, I take the extra step of re-sterilizing the starting mix. Some might say I’m being extra cautious but sometimes seeds are irreplaceable and need all the protection we can give them.

For small amounts of soil, I pour boiling water through a pot of starting mix — then go back and do two additional pours. If you decide to try it yourself, be sure to place the pot in a spot where the water can drain through easily. I like to do this outside on a wire rack rather than in the sink.

This boiling water method has been used by gardeners for a long time and has shown to be pretty effective. Since the entire volume of the soil mix will not reach 212 degrees Fahrenheit — the temperature at which it would be considered sterile — this could be considered more of a pasteurization method rather than actual sterilization technique.

Bob

Too much rain causes waterlogged garden soil

Gardeners in our area are having to deal with unusual amounts of water in their gardens. The amount of water in the soil is more like what we would see in early spring after the snow melt rather than late June or early July.

Driving around I see standing water all over our area with no place to go. Soils in many places are waterlogged which means big trouble for plants.

Most plants are able to cope with a day or two of flooding but after that, complications start to set in. The biggest problem is a lack of oxygen in the soil. Plant roots need oxygen to function.

All types of soil contain air spaces between soil particles. Fine textured soils with a lot of clay, have very small air spaces while sandy soils have large air spaces. This is very important because plant roots need access to soil air, they can’t efficiently use the oxygen dissolved in water.  When we have too much rain, these air spaces fill with water. Once that happens, the plant roots begin to drown and eventually die.

A water damaged plant, curiously enough, shows symptoms exactly like a plant that has been growing in a drought. In the case of a drought, there is not enough water for the roots to absorb so the upper part of the plant wilts. With a waterlogged plant, the upper part of the plant also wilts because can’t the roots have stopped working so no water gets moved into the upper parts of the plant.

After a the soil returns to normal, plants need to be watered more often because they have fewer roots. Often, if the damage is not too bad, the plant will recover by growing more roots to replace the ones lost by drowning. If it the damage is too great, the plant will be stunted and never be able to live up to its potential.

Raised beds are helpful in low lying areas.
Raised beds are helpful in low lying areas.

Another problem, especially with a vegetable garden, is the potential for contamination. In urban or suburban neighborhoods where all sorts of properties are nearby, there is the potential for flood waters to carry contaminants like bacteria or chemicals. Think of that dog kennel down the street or that parking lot with runoff water carrying motor oil and other debris.

You may want to think twice about eating vegetables exposed to contaminated flood water.

Bob