Archives for posts with tag: soil deficiencies

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.

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One vegetable dies, another takes its place.

One plant germinates, sprouts its tiny stems, spreads its leaves, grows larger, offers its colorful blossoms to eager pollinators, sets fruit, and then gradually, or sometimes quickly, puts forth a bounty of shiny produce to the gardener who tended it.

And then, more quickly, the plant fades away, its produce picked and its energy spent. No more pretty flowers or tasty vegetables. Most plants simply wither away at this point although biennials will contentedly continue to absorb and store energy for their flowering the second year (not having flowered or produced seed in the first).

Depending on the time of year and the climate, that leaves a vacancy in the garden, a void that would be wasted if left unfilled. If it is early enough in the summer and the first frost is not expected until late fall, there is plenty of time for a fast-growing vegetable—radishes are a good example—to repeat the cycle of life and death before winter descends.

That’s how succession gardening is supposed to work, anyway.

In the best planned garden, there is more to it than squeezing a second round of produce into the growing season. With careful selection of the first vegetable planted, when it is through the soil will be well prepared (even if depleted in some respects) for the plant that follows it. Likewise, the second vegetable, if chosen with thought, will leave the soil ready for what is sowed the next spring. This process can be stretched out over multiple seasons in what becomes long-term crop rotation (see May 18, 2014).

Theoretically, we follow this approach. In practice, we do the best we can. I’ve already described our crop rotation strategy (see May 4, 2014) and for succession planting, we do multiple sowings of root vegetables, including two or three early in the season and one late in the season, for which we are about due.

We also planted a mid-season replacement for the Sugar Snap peas, the last of which we harvested this morning. There were still plenty of peas but production had slowed and the leaves had begun to turn yellow. New growth had appeared at the base of several vines and I was tempted to wait to see whether it would bear fruit. But wanting to move on, we pulled them out.

In their place we sowed string beans. We planted the same varieties as last year—Amethyst Purple and Roma II—knowing that they are fast-growing and prolific (assuming the seeds are still viable, of course). I don’t know whether string beans are a good successor to peas in terms of soil conditioning but I do know that they are the only other vegetable we grow that needs trellising.

Also, I love to eat them.

My second least favorite garden activity: Digging holes in our rocky, clayey soil. (Long-time readers of this blog know what my least favorite garden activity is; new readers can look at January 7, 2012 for a clue.) Unpleasant as it is, I have to face up to it if I want to be ready in time to plant summer squash and cucumbers over the Memorial Day weekend. More specifically, I need to start digging if I want to plant them in a different place from last year.

And I do want to plant them in a different place. Most gardening experts advise rotating crop locations every year. Moving vegetables in the same family around the garden helps protect them from insects and diseases that can hunker down in the winter and lie in wait for the new season’s plantings. Given our problems with cucumber beetles, aphids, bacterial wilt and powdery mildew, it is worth the effort.

Many sources advise a four-year rotation. Because crop rotation also helps balance demands on the soil (heavy feeders one year, light feeders the next), the suggested schedule sometimes includes a season of so-called green manure (peas, buckwheat, winter rye, alfalfa) to replenish nutrients or a cover crop to stifle weeds. I love the concept even if we cannot afford to lose any planter space to vegetables we do not plan to eat.

Any separation of the rotating groups is beneficial but to be maximally effective, there should be as much distance as possible between the individual planting areas. I’ve seen recommendations of up to a quarter-mile. That sounds good for large-scale growers but a quarter of a mile from my garden is practically in the next county. We’re very limited by the space available to us.

So we do the best we can. We have two raised planters and each year we alternate what goes into them. Last year, we planted cucumbers behind the west planter; this year, we will move the cukes to a similar location behind the east planter. And after laying out a dozen mounds for squash, we only dug and planted half of them last year, in a staggered arrangement. This time around, we’ll plant the other six. The separation is not huge but it’s not zero, either.

Which leads me back to the digging. It’s not my favorite activity but when it is done, the garden will be in a better state (and I shouldn’t have to do it again next year).

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.

At breakfast last Saturday morning (pancakes and eggs at our favorite local joint), we started in on early planning for this year’s garden.  The first thing we concluded is that we are not really early.  By some reckonings, we should have sowed seeds for thyme last month and could be starting other herbs right now.  The second thing we concluded is that, once again, we are behind schedule.

Luckily, the choices of what to plant this year were relatively easy decisions even though a fair amount of thought went into each one.  We started with the list of plants we grew last year and then applied a few different criteria to assess their success.

The most important criterion for each vegetable is our answer to the question, did we like it?  It doesn’t matter how well it grew or how much it produced if, at the end of the day, we won’t eat it.  Of last year’s crops—those that actually yielded fruit—the only one that did not absolutely thrill us was the Aunt Ruby’s German Green tomatoes.  They were not bad, per se, but they didn’t leave us wanting for more.  Consequently, we will not grow them again this year.

There was one plant whose fruit we could not taste.  The Delicata winter squash did set fruit—several of them—but was not able to develop any of them to maturity.  And that leads to the next criterion, performance.  Plants that did not thrive last year may not be suited to our particular microclimate.  Then again, we may not have given them what they needed, either.

So, what besides the Delicata did not perform?  Well, the Kabocha winter squash produced only one specimen by the end of the year and it was a small one at that.  That’s two strikes against the winter squashes and based on this meager showing, I was tempted to say that we should try other varieties this year or skip them altogether.

However, roasted with a little olive oil and salt, the Kabocha squash was absolutely delicious.  It passed the first criteria with flying colors even though it showed weakly on the second.  Similarly, although we were not able to sample the produce of our Delicata, it is one of my favorite varieties (we often buy it at the farmers’ market).  Therefore, we will try the Delicata and Kabocha squashes again.

The next criterion then is, why did these vegetables underperform?  My best guess is that we underfed them.  I haven’t reported on last year’s testing yet (look for a future posting) but soil properties are a definite suspect.  The areas we planted with the squash were newly formed last year and have not had much chance to stabilize.  This spring, we will probably need to enrich their soil and fertilize them more frequently.

The same could be true of the summer squashes—both the yellow crookneck and pale green zucchini—and the cucumbers—one a pickling variant and the other a slicing type—all of which we planted in more or less the same area (the ground surrounding the planters) and with roughly the same soil (equal parts of compost and peat moss).

Despite these similarities, however, their performance was quite different.  Three of the four summer squash vines were hugely productive (especially the alpha crookneck; see August 6, 2013) whereas the cucumbers produced only a modest quantity of fruit before fading away in mid-summer.  Two other factors could account for the differences.

First, the amount of soil we introduced for the cucumbers was much, much less than for the squashes.  This is partly because of their location between the pool fence and planters but mostly because the cucumbers were the last seedlings we planted.  By that time, we were tired!  Our native soil is rocky and very difficult to dig but we will have to face up to doing more of it this year.  Adding to and amending the soil will be an early spring chore.

Second, the cucumbers were stricken hard by powdery mildew and once afflicted, perished rapidly.  It is not clear (and probably never will be) whether this was due to their undernourished state or simply because the varieties we planted are more susceptible than others to powdery mildew.  The squashes, on the other hand, seem better able to continue to produce after contracting the disease.  Each of the squash vines was still setting fruit into the fall.

Both of these are factors we can mitigate—or try to mitigate, anyway—and so we will plant both types of summer squash and both types of cucumbers again.  To help control the powdery mildew (which is endemic in the northeast), we will plant in new locations.  I will also arm myself with a spray bottle full of baking soda solution which I will apply early and often.  With diligence—and luck—we will have more squash and cucumbers than we can eat this year.

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.

Having harvested the last of the string beans (see September 25, 2013), we decided it was time to clear out the vines and start readying the west planter for winter.  Some gardeners would chop up the vines and till them into the soil to decompose and add organic matter (so-called green manure or green fertilizer).  Others might cut the stems off at the ground surface and leave the roots in place, hoping that symbiotic bacteria (if present) would continue to fix Nitrogen in the soil.

But neither of these ideas appeals to me.  Even though the planter is not that big (four feet by 12 feet), turning the soil would be a lot of work.  And anyway, we are following the no-till approach, which moderates decomposition, improves drainage and minimizes weed growth by leaving the soil surface undisturbed.  Somewhat ironically, it also maintains better aeration by eliminating compaction and encouraging the earthworm population.  In fact, our soil is essentially turned over several times a year by an abundance of energetic Lumbricidae.

Leaving the roots in place would require less effort—even less than pulling them out.  However, we do not necessarily have Nitrogen-fixing bacteria and it is not clear that they would have enough time to make a significant contribution to the properties of our soil.  Besides, it is more likely that we have too much Nitrogen rather than not enough (see June 22, 2013), as evidenced by our crops of carrots, beets and radishes which produced more leaves than roots.

Being completely honest, it probably wouldn’t matter if either alternative had a scientific justification because pulling the vines out is more in keeping with my nature.  I have been described as a neatnik and it is a characterization I do not deny.  At a certain level, getting the planter tidied up for its long winter nap is much more important to me than ensuring that the soil has a proper concentration of Nitrogen.  Our soil’s nutrient distribution can be adjusted in other ways and at other times but I have to look at the empty planter all winter long.

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).