Archives for posts with tag: soil pH

It would be hard to tell from this blog (because I have posted so few real-time entries since mid-fall, 2014) but I decided not to send any soil out for testing this year (well, technically speaking, last year).

During the previous three seasons (2011, 2012, and 2013), I collected soil samples in late September or October (see October 19, 2013, part 2 for the most recent account) and sent them off to the Rutgers Soil Testing Laboratory. Two weeks after that, the lab sent me via e-mail me a report of our soil’s properties (see February 14, 2014 for discussion of the October, 2013 results).

It was a worthwhile endeavor—information is power, and all that—and we made some adjustments that I am sure were of benefit to the vegetables. Probably the most significant factor that the tests brought to our attention was soil pH. Initially, it was too high and the following year (2012), we added Sulfur to bring it down.

But after that first year, we did not learn anything new. Our soil’s pH has stabilized within the optimal range and both the macro- and micronutrient levels have remained constant. The soil appears to have reached a healthy equilibrium and as a result, there have been no recommendations for change. And as they say, if it ain’t broke, don’t fix it.

This year, the vegetable plants themselves are telling me everything I need to know. Almost all are very happy so the soil must be okay.

More snow yesterday—a lot more snow—means that it is still too early to be thinking about starting any work on the garden outside.  At this rate of snowstorms, we won’t be digging out until March.

That is just as well because there are still a few items from last year to recap.  Most notably, there are the results of the soil testing that arrived at the end of October (2013) but which I have not had a chance to discuss.

Based on the previous year’s testing, I was not expecting any startling new information for the east and west planters (see October 19, 2013, part 2).  Sure enough, the reports confirmed my expectations.  The all-important pH of the soil remains within the sweet spot (6.20 to 6.80) for vegetable gardens with the east planter at 6.57 and the west planter a tad more acidic at 6.23.

Interestingly, the soil pH of the east planter increased slightly (from 6.31 in 2012) while the soil pH of the west planter decreased (it was 6.78 in 2012).  The soil in the east planter is now squarely within the preferred range but the soil in the west planter is bouncing from endpoint to endpoint.  Both are perfectly fine, however, and we will not have to make pH adjustment to either.

Similarly, the macro- (Ca, K, Mg and P) and micronutrient (B, Cu, Fe, Mn and Zn) concentrations in the east and west planters are close to each other, a result, I think, of at least three factors.  First, we treat the planters identically; neither has received any amendments (other than a top dressing of compost at the beginning of the season) or more fertilizer than the other.

Second, we have been rotating crops back and forth between the planters.  Therefore, their soils have been depleted (or replenished) by more or less the same amount.  Third, the age of the soil in each planter is more than two years.  I assume that given their consistent treatment, both soils are converging on the same steady state.

For the most part, the micronutrient levels in the west planter decreased when compared to last year (i.e., 2012).  This is not too surprising, again considering that we don’t heavily fertilize or otherwise modify our soil during the growing season (I think of it as time smoothing the soil’s rough edges).  Micronutrient levels in the east planter are mostly the same as 2012 (its soil is older and smoother).

What I didn’t expect is that in both planters, the concentration of Calcium increased by almost 50 percent.  We did not add lime, bone meal or any other source of the micronutrient so I have no idea from where the additional Calcium comes.

So much for the well-established planters.  On to the ground level soil, where we planted squash and cucumbers last season.

For starters, the pH of this soil is too high at 7.10 (the soil is slightly alkaline).  We’ve learned from both of the growing seasons prior to last that this can have a very detrimental effect on plant performance.  And I learned from this year’s experiments with seed starting mix that the culprit is probably not the very acidic peat moss, of which the ground level soil is roughly half.  The other half is compost (mainly cow manure) which tends to be more alkaline.

When we dig new pits for the squash and cucumbers this year, we will have to increase the proportion of peat moss to manure and perhaps add some elemental Sulfur to bring the pH down.  Otherwise, the ground soil profile resembles that of the planters.  The macro- and micronutrient concentrations are very close, including—somewhat mysteriously—the high concentration of Calcium.

This is a bit ironic because the summer squash plants experienced a high rate of blossom end rot last season, a condition that is usually associated with Calcium deficiency.  I think this is what the testing lab was alluding to when they called me in the fall (see October 24, 2013).  The testing methods based on acid extraction indicate a high concentration of Calcium but it is not, apparently, in a form that plants can readily use.  I’ll have to look into this one further.

The reports list lots of numbers, not all of them obviously meaningful.  So, what does it all mean?  The bottom line is that our planters’ soil is doing fine and that with minor modification the soil in the ground will come into line as well.  That’s good—if not exciting—news.

I’m happy to report that the 2014 growing season is officially under way.

In our garden, anyway.  Having assembled all of the necessary parts, I found some time this afternoon to sow seeds for the herbs.

As a first step, I washed the mixing tub, seed tray and trowel with a mild bleach solution.  All of these items were used last year and have been stored in the basement since.  The exposure to outside elements is high and given the dark and damp conditions down here, the potential for mold and harmful bacteria is great.

Then, I mixed up a batch of seed starting medium.  I measured out quantities of peat moss, vermiculite and perlite (in a 2:1:1 ratio) to equal a half gallon of dry volume and dumped them into the tub.  The lime I purchased is pelletized so I used a mortar and pestle to pulverize it into smaller particles.  A quarter teaspoon per gallon—an eighth of a teaspoon for this batch—seemed much too small; I used a teaspoon.  To be more accurate, I would need to know the pH I was starting with.

Using a spray bottle, I moistened the mix and stirred it with the trowel.  Peat moss is extremely dry and perlite can absorb a lot of water so I had to repeat this process for several cycles.  When the moisture content seemed right—damp but not soggy—I spooned the mix into a half seed tray (that’s 36 compartments) and tamped it in lightly.  It turns out that half a gallon of seed starting mix is just the right amount.

Next came the seeds.  We will be planting basil again this year (last year’s did extremely well) along with the herbs we purchased seeds for last year but never managed to plant:  rosemary, thyme, oregano, spearmint and sage.  Because most herb seeds are very small, I used tweezers to drop one or two seeds into a shallow hole (formed using a pencil as a dibble) in each compartment.

After covering the seeds with a pinch of mix (the recommended sowing depth for herbs is only 1/4 to 1/2 of an inch), I gently sprayed the tray with water until it ran out of the bottom.  For most of the herbs, this will be the only water they get until they germinate and emerge from the soil 10 days (or, in the case of the rosemary, 28 days) from now.  I set the covered tray atop a heating pad on a shelf of the seed starting apparatus, turned on the pad and fluorescent light and made sure that the timer was properly set.

Like all seed sowing, starting the herbs is an act of faith.  This is especially true for the oregano and spearmint whose seeds are teeny-tiny (they are packaged in small zip-top plastic bags within their paper seed packet).  I can’t be sure whether any seeds actually made it into the soil or from which tray compartments they will sprout.

But I firmly believe that they will and I will be thrilled when they do.

Yesterday, we made a run up to the Adams Fairacre Farms store near us.  They have a well-stocked garden center, open all year, and we went there to procure seed starting mix.  We also found an amazing selection of seeds, including those of the Hudson Valley Seed Library about which I wrote last year (see January 5, 2013).  Good to know in case we decide to buy more seeds this year.

They had at least three brands of seed starting mix on offer, all different from the brand we used last year.  The ingredient lists looked similar and included a combination (in proportions not disclosed) of peat moss, vermiculite and/or perlite.  Some also contained compost or other fertilizers (most notably, the Miracle-Gro product which boasts both Miracle-Gro Plant Food and MicroMax nutrients).  These are superfluous for seed starting; the seed itself contains everything the plant needs from germination until leaf growth.

After browsing the available mixes and looking over the extensive array of soil components and amendments also for sale, I decided to make my own seed starting mix this year.  I recalled from my previous research that all that is really needed is peat moss, for structure, and vermiculite, for water retention.  I have more than a bale of peat moss left over from last year and picked up a bag of vermiculite to add to it.

Today, I decided to do a bit more research to determine what the best ratio of materials might be.  I didn’t find any definitive answers—as with most topics, there are a lot of opinions out there—but I did perceive two common threads.  First, many gardeners recommend adding perlite to keep the mixture lightweight and to facilitate drainage.  Second, several others suggest including a small amount of lime to balance the low pH (high acidity) of peat moss.

I made another trip to Adams (luckily, it is not far away) to buy the perlite and lime.  A definite advantage of the do-it-yourself approach is that all of the mix components are cheap.  For less than $20, I will have enough mix for this year’s seedlings, including potting up.  The lime will last substantially longer (in fact, I will probably never have to buy it again).

When combining the components, I will initially mix two parts peat moss to one part each of vermiculite and perlite. One recipe called for a quarter teaspoon of lime per gallon of mix, which seems low but is as good a starting point as any.  After that, I will adjust as needed to produce a consistency that seems right.

This is a case where my intuition will have to guide me.

After returning home from running errands this afternoon, I was surprised to find a voicemail message from the soil testing laboratory.  This is the third year I’ve sent them soil for analysis and I did nothing different this year compared to the previous two years.  What could the issue be?

I gave the lab a call back and learned that they were concerned that the tests I requested might not be appropriate for our soil.  Based on a brief visual assessment of the soil samples and their labels (“East Planter”, “West Planter”, “Ground Level”), and without checking the type of planting for which the soils would be used (as I had indicated on the back of the soil test questionnaire), the lab scientist thought that perhaps I worked for a mall and was checking the soil from its indoor flower beds.  I’m not sure whether to be flattered (or not).

It turns out that the basic soil tests I commissioned are intended for mineral-based soils and use acids to extract the nutrients of interest.   This method is efficient and quick and yields reliable results for total nutrient content.  However, for soils that have very high concentrations of nutrients in mineral form, the observed values may not represent how much of the nutrients are actually available to plants.  For example, a clod of partially decomposed ore may be rich in iron but spinach still won’t grow well in it.

Alternatively, for compost and other soils rich in organic matter, extraction by water solubility is usually employed.  Apparently, this method takes longer and is somehow more complicated (I infer, because it costs much more) but produces values that are closer to what is readily available to a plant’s roots.  I explained our soil’s situation—it is used for a vegetable garden—its composition—it is a mix of compost, peat moss and native soil—and its history—she looked up the previous years’ reports—and weighing this information, she decided the basic tests would be okay.

The soil scientist said that many people are (and here she groped for a politically appropriate word) enthusiastic about adding organic matter to their soil, by which I believe she meant to imply that they add too much.  Looking at our previous reports, however, she saw that although some of our nutrient levels are high (“above optimum” is the lab’s term), the values are not off the charts.  I think she concluded that the total and available concentrations of nutrients in our soil should not be too different.

Looking more closely at our previous analysis results, she liked that our soil pH was in the green zone (6.20 to 6.80) last year and noticed that in our first year (the east planter only, in 2011), our pH was high.  I reported that based on the report, we adjusted the pH by adding elemental Sulfur and that was probably why we were at the proper acidity by the end of the 2012 season.  She was happy to hear that someone actually followed their recommendations.

The lab will start the soil testing tomorrow and I hope to hear back from them next week.

It’s that time of year again (past time, actually):  Time to send the soil out for testing.

Why is it that time?  Because the growing season is over and the soil is as depleted as it will get this year.  Now is the time to add supplements or nutrients that the soil may need before the new season starts in spring.  And I won’t know what to add without an assessment of what is—or is not—there.  Also, the planters are (almost) bare so it is convenient to take samples.

Testing is becoming less critical for the east planter, which has just completed its third year of service.  Its soil needed adjustment after the first year (to increase its acidity) but received no amendments last year.  We did add a small amount of compost (to bring the soil surface higher) and may do so again this year.  Otherwise, I don’t expect that the soil’s properties have changed much.

Similarly, the soil in the west planter was nearly on the mark in terms of pH and nutrient concentrations, as evidenced by its first soil testing last year (see October 4, 2012).  It received the same treatment as the east planter (a minor infusion of compost) and in conjunction with the solid performance of this year’s crops, is unlikely to need any modifications.

The condition of the newest soil in the garden, the mounds where we planted the squashes and cucumbers, is another matter entirely.  We were not particularly careful in designing this soil and simply mixed together roughly equal parts of compost and peat moss.  It looked right and was good enough but apparently only just so.  While the summer squashes performed adequately (especially the yellow crookneck), the winter squashes and cucumbers did poorly (in fact, only one Kabocha and none of the Delicata squashes reached maturity).

Clearly, there is something missing from (or otherwise not quite right with) this soil.  Testing should help uncover what that is.

As in previous years, for each of the planters and the mounds, I dug soil from four locations, mixed it together and dumped it into a labeled zip-top bag.  I slipped each baggie into a larger one (to contain possible spillage) and packed the three sacks into a box for shipping.  To the box I added the testing lab’s forms (one for each sample) and a check to cover expenses.

Next week, I’ll send them to New Jersey and in another week to 10 days, we should have the results.

What I’ve learned about beets:  First, they need less Nitrogen than flowering plants and relatively low soil pH (i.e., slight acidity).  Our soil is at the high end (6.78) of the preferred range (6.2 to 7.0), based on last fall’s soil report (see October 4, 2012), and I infer that our Nitrogen level is also high (last year’s report recommended adding only nominal amounts).

Second, beet seeds are clustered.  What looks outwardly like a single seed is actually a seedball consisting of three or four seeds held together by an outer layer.  This redundancy helps insure that the plants successfully reproduce—each seedball is three or four times more likely to produce a new plant—but for the gardener, it can be too much of a good thing.  Under favorable conditions, all of the seeds will germinate and if all of the seedlings are left to mature, the result will be plants that are so closely spaced that there is no room for the roots to develop.  Even with careful sowing, therefore, thinning will be required.

Third, while the beet greens can grow quite quickly, the beet roots will sometimes grow very slowly.  This condition arises in part from the higher Nitrogen concentration in the soil—which promotes vegetative growth—and is dependent on temperature as well.  We had a cool spring during which the beet seeds rapidly germinated and produced lovely heads of dark green leaves.

Then, before the roots could catch up, the weather turned warm and the beets’ development slowed.  We kept them well hydrated, so they were not permanently damaged by the heat, but their growth was stunted.  I will do some research into how to minimize the Nitrogen effect (it is not clear what nutrients would promote root growth) and with luck, next year’s beet roots will develop earlier, before the hot weather arrives.

Fourth, beet roots can go a long time unharvested, even in high heat, with no detrimental effects.  We discovered this when we pulled out the first row (see July 28, 2013) and found the beets to be in good condition even though they had been in the ground for months.  It makes sense, botanically:  The roots store solar energy collected during the beets’ first year of growth in order to produce flowers and seeds during their second year.  It makes beets a good choice for busy people.  Unlike more delicate vegetables like tomatoes, which will rot if left unpicked for too long, beets will wait patiently in the garden with no ill effects until their grower is ready for them.

What I already knew about beets:  They are absolutely delicious, especially when roasted, which intensifies their flavor.  And the greens might be more delicious than the roots (they are certainly more nutritious).  Beet greens make a fine addition to salads when they are young and hold up as well as, if not better than, spinach when sautéed.

We are still experiencing blossom end rot of the crookneck squash.  It is not affecting every fruit, however, and despite losing two or three potential squash, we were able to harvest two healthy ones.

At the same time, we also picked two of the Cavili zucchini.  These turn out to be a pale green variety (as opposed to the more typical dark green type) and are best picked small (about four inches in length).

Blossom end rot is caused by a deficiency of Calcium in the soil.  The soil in which our squash plants are growing should be rich in minerals but it is new, by which I mean it has not been tested; we do not know its balance of macro- and micronutrients.  It could easily be short on Calcium or perhaps overly acidic.

We have a friend who swears by bone meal.  Whenever she plants a squash or tomato plant, she sprinkles a handful of it into the bottom of the hole.  That way, she knows that the plant will have a ready source of Calcium.  We have rarely done this (based on the results of soil analysis and, admittedly, laziness).

We’ll keep an eye on the squash plants and if the end rot persists, will consider adding Calcium in some form (bone meal is slow so a liquid form may be more efficacious).

I finally found some time to look at the soil test reports and to compare them to each other and to last year (less to do in the garden means more time to spend doing other things).  The results were neither earth-shaking nor even startling but there were some changes, all of them for the better.

First—and most important—the soil pH for the east planter fell to 6.31, well within the optimal range (as recommended by Rutgers) of 6.20 to 6.80.  Last year, the pH was at 7.38, or slightly alkaline, and too high for most vegetable plants.  We added elemental Sulfur in the spring (see February 20, 2012) and it appears to have done the trick.

Similarly, the soil pH for the west planter was in the acceptable range—just barely—at 6.78.  The main difference between the soil in this planter versus the soil in the east is a lower proportion of compost.  Therefore, it would appear that the compost has a higher pH than the soil or peat moss.  By using less of it, we started with a lower pH than we did with the east planter last year.  For both planters, we will not need to make any adjustments (no Sulfur, no limestone) next spring.

Of lesser importance (and, perhaps, interest), the concentrations of macronutrients—Phosphorus, Potassium, Magnesium and Calcium—in the east planter have decreased, although all but one remains above optimum.  The exception is Potassium, whose concentration has dropped into the optimal range (whatever it is; the optimal ranges are not noted in the report).  The reduced Potassium concentration and the still-high Calcium concentration are consistent with the drop in pH and the recommendation not to add limestone (which is mainly Calcium Carbonate).

The macronutrient concentrations in the west planter are very close to those in the east with the exception again being Potassium.  Its concentration is higher and very near to what it was in the east planter last year.  That might explain why the west planter’s pH is higher.  The interactions between macronutrient concentrations and pH are very apparent from the testing results.

Finally, the concentrations of micronutrients—Zinc, Copper, Manganese, Boron and Iron—in both planters remain more or less the same.  They are for the most part classified as adequate (with no explanation of what that means) with Manganese and Iron falling into the high category.  These concentrations do not seem to have much impact and all are deemed not a limiting factor by the lab techs.

The bottom line is that as long as we maintain pH in the optimal range and continue to use balanced fertilizers, our soil will be just fine.