Back in May I posted about using the scientific method to conduct a dialogue with my garden in my effort to learn to work more skillfully with Nature’s patterns. While I want to grow a lot of food in a small space (and perhaps inspire some of you to do the same thing), I also want to leave that small space better than I found it. In order to do that, I have been conducting an informal scientific dialogue with my garden for the past 15 years. In the linked post I discussed how I use the scientific method to help me become a better gardener as well as the particular questions I asked my garden to answer this year. Now that most of the harvest is in, it’s time to find out what my garden told me.
In early 2013 I had learned about soil re-mineralization and its beneficial effects on gardening from Steve Solomon’s 2013 book The Intelligent Gardener: Growing Nutrient-Dense Food. The result was that the major question I asked my garden to answer this year is, what effect would proper soil mineralization have on the yields that I am able to obtain? I wanted to know the answer to this question because I am trying to grow a larger fraction of the vegetables that Mike and I eat, and some evidence suggested that lack of a properly balanced soil mineral base might be one issue that is keeping the yields I measure lower than what appears to be possible.
To help answer this question, I had a soil test done by the laboratory Steve Solomon recommended early in the gardening season and used the process in his book to develop a complete organic fertilizer tailored to remedy the mineral deficiencies in my garden soil that the soil test revealed were present, as I discussed in this post. Then I formulated a set of questions for the garden to answer in 2013, in the form of hypotheses that I thought were reasonable to expect from a more appropriately mineralized soil. The hypotheses were:
- Yield, defined as pounds harvested per 100 square feet, should increase for those varieties I grew in 2013 that I have also grown in past years, or at least not decrease.
- Those minerals that were in excess in my soil at the start of the gardening season should show a reduction in excess, and those minerals that were deficient should show a reduction in deficiency, by the end of the growing season.
- Varieties that I have grown in past years might have improved flavor and/or improved pest and/or disease resistance this year.
Besides these questions, I also grew several new varieties of vegetables to see if the new varieties offered any improvements versus the ones I have grown in the past.
Now that most of the rest of the harvest is finished and the 2014 seed catalogs are hitting my mailbox, it’s time to finish the analysis so that I can decide on the questions I’d like answered in 2014. Because some of you might be interested in the data (not to mention checking to see if my analysis is correct), I’m reporting it below. But many of you just want to know the conclusion. So for you, a summary of what my garden told me:
Yields were affected by many different factors, but in the few cases where the effect of soil re-mineralization could be clearly discerned, it was positive.
Taste was mostly not affected, but a few varieties seemed to taste better. Pest and disease pressures were reduced compared to previous years.
The effect of soil re-mineralization on post-season mineral levels is unclear and will require a lot of thought to determine what the soil told me and how to respond.
This year’s results were sufficiently positive that I’ll re-balance the soil minerals next year and see what my garden tells me as a result. No doubt I’ll ask other questions of my garden in 2014. Once I’ve formulated them, I’ll put up a post or two on what my garden and I will be discussing in 2014.
___________________________
Now for those of you who want to see all the data and my analysis of it, and for those of you who might be considering if you want to ask your gardens some questions in 2014 or make use of my results in your gardens, keep right on reading. It’ll be a long post so you might want to have your favorite long-post-reading beverage at hand.
While you read the following, keep in mind these different aspects of the art of scientific dialogue:
- knowing what questions you want to ask;
- knowing how to set up the dialogue so the garden gives you the answers to the questions you asked rather than to some other questions you didn’t realize you asked till the end of the season; and
- figuring out what questions you, the garden, and the larger environment asked that you weren’t aware of or could not have known at the start, and how those questions affected your ability to answer the questions you wanted to ask.
Because I’m working with a living system that is inherently powerful and unpredictable and that is connected to a far more powerful and unpredictable environment, I have to accept that the garden and the environment will ask and answer some questions of their own which may hinder how well some or all of my questions can be answered. Among those questions this year were the effect of a hot, dry fall on the fall lettuce, which prevented my obtaining an answer to the question of which of the lettuce varieties I tried to grow did best in the fall garden.
As I expected, I did not ask the question about yields as skillfully as I could have because I allowed too many other controllable aspects of gardening to vary. Among those, I did not include controls (varieties I’ve grown in the past) for some of the crops that I grew, and I did not plant some crops at the same spacing as I did in the year in which I had the highest yield. Since not all varieties perform the same even when everything else is held constant, not including a control often prevented me from determining if the yield in 2013 increased for that crop. Similarly, since yields depend on crop spacing, in those cases where I changed spacing for a control variety I could not determine if the yield increased in 2013. Such is life. Since I didn’t decide to ask the question about the effect of soil re-mineralization till I had already planned out the garden, purchased seeds, and started some of the plants, I knew that I didn’t design my garden trials as well as I could have to obtain the answers I wanted. But I still grew lots of food and enjoyed myself and learned a lot from my garden. And as they say, there is always next year.
Back to learning what my garden told me. I’ll address the three big questions I asked it in turn.
Question #1: did soil re-mineralization result in increased yields?
The best way to answer that question would be for everything else – weather, planting dates, crop varieties and spacing, added compost amount and composition, and so forth – to be exactly as it was in previous years, with only the soil fertilization added to each bed changing. The weather varies a lot from year to year and that inevitably affects how well I can answer any gardening question. In addition, I have changed crop varieties, spacing, and planting dates for some of the crops that I have grown over the years and changed how much compost is added to each bed, as well as other (sometimes unintended) changes. In order to disentangle effects due to re-mineralization from effects that might be due to some other change, I’ll start with a table of the previous highest-yielding varieties of various crops along with the varieties that I grew this year. I’ll include the recommended spacing from the 8th edition of the bookHow to Grow More Vegetables by John Jeavons, the spacing and planting date for the year in which I got the best yield previous to 2013, and the 2013 spacing and planting date.
Table 1. Planting information for highest yielding crop varieties and varieties planted in 2013.
|
Crop
|
Variety
|
HTGMV spacing, inches
|
Past spacing, inches
|
Past planting date
|
2013 spacing, inches
|
2013 planting date
|
|
Dry bush bean
|
Midnight Black Turtle
|
6
|
In-row 6, between-row 6
|
5/18/09
|
|
|
|
Dry bush bean
|
Beefy Resilient Grex (F4)
|
6
|
|
|
3 seeds planted in each spot; in-row 12, between-row 12
|
6/12
|
|
Beet
|
Cylindra
|
4
|
In-row 4, between-row 4
|
4/15/12
|
In-row 6, between-row 6
|
5/17
|
|
Beet
|
Sugar
|
7
|
In-row 6, between-row 6
|
5/23/11
|
In-row variable, between-row 12
|
5/17
|
|
Bok choy
|
Prize Choy
|
Not given
|
12
|
Sown 2/28/10, TP 4/24
|
12
|
Sown 2/15, TP 5/13
|
|
Broccoli
|
Green Goliath
|
15
|
15
|
Sown 2/1/06, TP 4/14
|
|
|
|
Broccoli
|
Nutri-Bud
|
15
|
15
|
Sown 2/7/12, TP 4/19
|
15
|
Sown 2/15, TP 5/11
|
|
Cabbage
|
Early Jersey Wakefield
|
15
|
15
|
Sown 2/1/06, TP 4/14
|
15
|
Sown 2/15, TP 5/11
|
|
Cabbage
|
Golden Acre
|
18
|
|
|
18
|
Sown 2/15, TP 5/11
|
|
Carrot
|
Danvers 126
|
3
|
In-row 4, between-row 4
|
4/15/12
|
In-row variable, between-row 6
|
5/17
|
|
Corn, flint
|
Cascade Ruby-Gold
|
15
|
|
|
In-row 12, between-row 12
|
6/24, 6/27, 6/28
|
|
Corn, pop
|
Unknown yellow
|
15
|
In-row 12, between-row 24, 3 to 4 seeds per spot
|
6/21/09
|
|
|
|
Eggplant
|
White (store-bought)
|
18
|
In-row 12, between-row 12
|
Planted 5/11/12
|
|
|
|
Eggplant
|
Black Beauty
|
18
|
|
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/22
|
|
Eggplant
|
White Beauty
|
18
|
|
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/21, 5/22
|
|
Garlic
|
Inchelium Red
|
4
|
4
|
Planted 11/16/99
|
In-row 6, between-row 6
|
Planted 11/10/12
|
|
Leek
|
Giant Musselburg
|
6
|
6
|
Sown 2/1/06, TP 4/14/06
|
|
|
|
Leek
|
Bleu de Solaize
|
6
|
6
|
Sown 2/3/12, TP 3/29
|
In-row 6, between-row 12
|
Sown 1/22, TP 4/24
|
|
Lettuce
|
Anuenue
|
12
|
9
|
Sown 3/7/11, TP 5/7
|
9
|
Sown 3/13, TP 5/13
|
|
Lettuce
|
Bronze Arrow
|
12
|
12
|
Sown 3/7/11, TP 5/7
|
12
|
Sown 3/13, TP 5/13
|
|
Lettuce
|
Pirat
|
9
|
9
|
Sown 2/28/10, TP 4/23
|
9
|
Sown 3/13, TP 5/13
|
|
Onion, multiplier
|
Potato
|
Not given
|
6
|
Planted 11/26/05
|
8
|
Planted 11/10/12
|
|
Onion, bulb
|
Dakota Tears (yellow)
|
4
|
In row 6, between-row 6
|
Sown 2/28/10, TP 4/8
|
In-row 6, between-row 12
|
Sown 1/22, TP 4/24
|
|
Onion, bulb
|
Rossa di Milano (red)
|
4
|
6
|
Sown 2/3/12, TP 3/28
|
In-row 6, between-row 12
|
Sown 1/22, TP 4/24
|
|
Pea, shell
|
Little Marvel
|
3
|
In-row 6, between-row 6
|
Sown 4/3/12
|
In-row 6, between-row 6
|
Sown 4/5
|
|
Pea, snow
|
Blizzard
|
3
|
In-row 6, between-row 6
|
Sown 4/3/12
|
|
|
|
Pea, snow
|
Oregon Giant
|
3
|
|
|
In-row 6, between-row 6
|
Sown 4/5
|
|
Peanut
|
Tennessee Red Valencia
|
9
|
|
|
In-row 12, between-row 24, 3 to 4 seeds per spot
|
Sown 6/3
|
|
Pepper, sweet
|
Carolina Wonder
|
12
|
|
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/21
|
|
Pepper, sweet
|
Italian Frying
|
12
|
12
|
Sown 1/27/07, TP 4/30
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/21
|
|
Pepper, sweet
|
World Beater
|
12
|
In-row 12, between-row 12
|
Sown 2/4/08, TP 4/30
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/21
|
|
Potato
|
Elba
|
9
|
|
|
In-row 12, between-row 24
|
Planted 5/1
|
|
Potato
|
German Butterball
|
9
|
In-row 12, between-row 24
|
Planted 4/18/11
|
In-row 12, between-row 24
|
Planted 4/30
|
|
Potato
|
Rose Gold
|
9
|
9
|
Planted 4/7/06
|
|
|
|
Radish, winter
|
Black Spanish Round
|
Not given
|
In-row variable, between-row 12
|
Sown 8/13/08
|
In-row variable, between-row 12
|
Sown 8/16
|
|
Radish, winter
|
Red Meat
|
Not given
|
In-row 6, between-row 6
|
Sown 7/20/09
|
In row variable, between-row 12
|
Sown 8/16
|
|
Squash, summer
|
Benning’s Green Tint
|
15
|
|
|
In-row 12, between-row 48
|
Sown 7/12
|
|
Squash, winter
|
Lady Godiva
|
18
|
In-row 48, between-row 48
|
Sown 7/6/09
|
|
|
|
Squash, winter
|
Sweet Meat – Oregon Homestead
|
18
|
|
|
In-row 24, between-row 48
|
Sown 7/3
|
|
Squash, winter
|
Waltham Butternut
|
18
|
In-row 48, between-row 48
|
Sown 7/2/11
|
In-row 24, between-row 48
|
Sown 7/11
|
|
Squash, zucchini
|
Dark Green
|
18
|
In-row 36, between-row 48
|
Sown 6/20/09
|
|
|
|
Squash, zucchini
|
Costata Romanesca
|
18
|
In-row 48, between-row 48
|
Sown 5/23/12
|
In-row 12, between-row 48
|
Sown 7/12
|
|
Sweet potato
|
Ivis White Cream
|
9
|
In-row 15, between-row 24
|
Planted 6/21/08
|
|
|
|
Sweet potato
|
O’Henry
|
9
|
|
|
In-row 12, between-row 48
|
Planted 5/29
|
|
Tomato
|
Arkansas Traveler
|
18
|
In-row 12, between-row 12
|
Sown 2/17/12, TP 5/12
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/22
|
|
Tomato
|
Hungarian Italian Paste
|
18
|
In-row 12, between-row 12
|
Sown 2/17/12, TP 5/11
|
In-row 12, between-row 12
|
Sown 3/13, TP 5/21
|
|
Turnip
|
Purple Top White Globe
|
4
|
In-row variable, between-row 6
|
Sown 8/16/08
|
In-row variable, between-row 12
|
Sown 8/16
|
In the table above and in the rest of the post, HTGMV refers to the 8th edition of How to Grow More Vegetables. HTGMV suggests planting on a triangular grid to maximize overlap of the crowns of the plants at maturity. The HTGMV column gives the spacing, in inches, to use for each crop according to the Master Charts in HTGMV. The Master Charts do not differentiate potato onions (a perennial onion that splits into smaller bulbs, grown by planting single bulbs in mid to late fall) from bulb onions, thus there is no entry in the HTGMV column for potato onions. Winter radishes are not differentiated from salad radishes and bok choy is not shown in the Master Charts so these also lack entries in the HTGMV column.
Table 1 shows that I now plant most varieties at a different spacing than HTGMV suggests and often in rows, sometimes short rows across the width of the bed (my beds are all 4 feet wide by 25 feet long), sometimes long rows down the length of the bed. Note how much farther apart I plant many varieties now than I did in the year when I got the highest yield, and how much some of the sowing and planting dates have changed. I’ll talk more about that when I discuss the yield results shown in Table 2 below.
Table 2. Possible yields from HTGMV, best previous yields, and 2013 yields. All yields are given in pounds per 100 square feet. The HTGMV column shows possible yields using the HTGMV method of gardening, based on Ecology Action’s research. They suggest beginners use the low number for planning and comparison purposes, good gardeners the middle number, and excellent gardeners with favorable climates and soil the high number. The next two columns are the best previous yield I have obtained with a variety and the yield I obtained for that variety in 2013. An asterisk shows harvests that have been completed but not yet weighed, thus yield data is currently unavailable.
|
Crop
|
Variety
|
HTGMV yield
|
Previous best yield
|
2013 yield
|
|
Dry bush bean
|
Midnight Black Turtle
|
4 / 10 / 24
|
12
|
|
|
Dry bush bean
|
Beefy Resilient Grex (F4)
|
4 / 10 / 24
|
|
*
|
|
Beet
|
Cylindra
|
110 / 220 / 540
|
34
|
104
|
|
Beet
|
Sugar
|
91 / 182 / 364
|
141
|
179
|
|
Bok choy
|
Prize Choy
|
Not given
|
182
|
121
|
|
Broccoli
|
Green Goliath
|
26 / 39 / 53
|
76
|
|
|
Broccoli
|
Nutri-Bud
|
26 / 39 / 53
|
12
|
40
|
|
Cabbage
|
Early Jersey Wakefield
|
96 / 191 / 383
|
167
|
77
|
|
Cabbage
|
Golden Acre
|
96 / 191 / 383
|
|
156
|
|
Carrot
|
Danvers 126
|
100 / 150 / 400+
|
122
|
187
|
|
Corn, flint
|
Cascade Ruby-Gold
|
11 / 17 / 23+
|
|
*
|
|
Corn, pop
|
Unknown yellow
|
11 / 17 / 23+
|
16
|
|
|
Eggplant
|
White (commercial strain)
|
54 / 108 / 163
|
151
|
|
|
Eggplant
|
Black Beauty
|
54 / 108 / 163
|
|
50
|
|
Eggplant
|
White Beauty
|
54 / 108 / 163
|
|
57
|
|
Garlic
|
Inchelium Red
|
60 / 120 / 240+
|
39
|
12
|
|
Leek
|
Giant Musselburg
|
240 / 480 / 960
|
107
|
|
|
Leek
|
Bleu de Solaize
|
240 / 480 / 960
|
96
|
34
|
|
Lettuce
|
Anuenue
|
75 / 150 / 300
|
90
|
113
|
|
Lettuce
|
Bronze Arrow
|
75 / 150 / 300
|
89
|
52
|
|
Lettuce
|
Pirat
|
75 / 150 / 300
|
104
|
68
|
|
Onion, multiplier
|
Potato
|
Not given
|
78
|
33
|
|
Onion, bulb
|
Dakota Tears (yellow)
|
100 / 200 / 540
|
44
|
18
|
|
Onion, bulb
|
Rossa di Milano (red)
|
100 / 200 / 540
|
54
|
34
|
|
Pea, shell
|
Little Marvel
|
25 / 53 / 106
|
17
|
10
|
|
Pea, snow
|
Blizzard
|
25 / 53 / 106
|
17
|
|
|
Pea, snow
|
Oregon Giant
|
25 / 53 / 106
|
|
5
|
|
Peanut
|
Tennessee Red Valencia
|
4 / 10 / 24
|
|
5
|
|
Pepper, sweet
|
Carolina Wonder
|
68 / 136 / 204
|
|
48
|
|
Pepper, sweet
|
Italian Frying
|
68 / 136 / 204
|
126
|
99
|
|
Pepper, sweet
|
World Beater
|
68 / 136 / 204
|
83
|
54
|
|
Potato
|
Elba
|
100 / 200 / 780
|
|
75
|
|
Potato
|
German Butterball
|
100 / 200 / 780
|
35
|
38
|
|
Potato
|
Rose Gold
|
100 / 200 / 780
|
111
|
|
|
Radish, winter
|
Black Spanish Round
|
Not given
|
123
|
15
|
|
Radish, winter
|
Red Meat
|
Not given
|
120
|
32
|
|
Squash, summer
|
Benning’s Green Tint
|
75 / 150 / 307
|
|
39
|
|
Squash, winter
|
Lady Godiva
|
50 / 100 / 350
|
87
|
|
|
Squash, winter
|
Sweet Meat – Oregon Homestead
|
50 / 100 / 350
|
|
71
|
|
Squash, winter
|
Waltham Butternut
|
50 / 100 / 350
|
47
|
22
|
|
Squash, zucchini
|
Dark Green
|
160 / 319 / 478+
|
44
|
|
|
Squash, zucchini
|
Costata Romanesca
|
160 / 319 / 478+
|
36
|
313
|
|
Sweet potato
|
Ivis White Cream
|
82 / 164 / 492
|
74
|
|
|
Sweet potato
|
O’Henry
|
82 / 164 / 492
|
|
64
|
|
Tomato
|
Arkansas Traveler
|
100 / 194 / 418
|
647
|
500
|
|
Tomato
|
Hungarian Italian Paste
|
100 / 194 / 418
|
948
|
458
|
|
Turnip
|
Purple Top White Globe
|
100 / 200 / 360
|
101
|
9
|
Knowing what the garden told me about yield for each crop I grew, I have to translate what it said into answers to the questions I asked as well as the questions I didn’t realize I was asking and that the garden and environment asked. To do that I need to discuss a number of factors that can affect yield in addition to soil re-mineralization. Then I’ll look at each crop in turn to tease out the different effects.
Crop Spacing. There is a complex relationship between spacing and yield. Crops that are planted too close together compete for nutrients and thus don’t yield as well on a weight per unit area basis. Increasing the spacing increases yields, but only up to a point. Once the spacing gets so large that some of the soil minerals go un-utilized by the crop, yield begins to decrease. HTGMV’s suggested spacing is supposed to be that for which yield is highest for each crop. Table 1 indicates that I have tended to use wider spacing than HTGMV suggests for many crops. This in turn suggests that my yields will tend to be low for those crops.
Planting date. Crops need to be planted at the time when the weather patterns are favorable for their growth and development. In general, that means that crops that like cool spring weather should be planted in late March or April here, while plants that need many weeks of warm to hot weather should be planted in May or June and crops that need cool fall weather should be planted from June through August depending on their maturity date. Examination of Table 1 suggests that in some cases I planted too late in 2013, based on both generally accepted planting dates for this area and the planting date I used in the year of highest yields.
Crop variety. Gardeners and farmers find that some varieties are better adapted for their conditions than are others. In general, the better adapted a variety is, the higher yield it can give, other factors being constant. In other cases certain varieties are larger or smaller than other varieties of a particular crop wherever they are grown. A larger variety planted at the same time and at the same distance might be expected to yield more than a smaller variety, unless excess competition becomes a factor.
Shading. Some of the crops I grew, notably the peppers and eggplants, were shaded by more-vigorous crops grown next to them. Shaded crops will not yield as much as their less shaded or un-shaded counterparts.
Nutrient demand. Some crops do not need as much nutrition as do others. Steve Solomon includes a table of low, medium, and high demand vegetables on page 16 of his bookGardening When It Counts. All else being equal, proper soil mineral balance might be expected to have the biggest positive effect on high-demand veggies and the least on low-demand veggies.
Weather conditions. Excessive heat, cold, rain, or drought compared to what is experienced in an average season can reduce the yield of crops susceptible to their effects. In 2013 spring proved to be cool and wet. June and July tended cool and wet while August through October were warmer and dry. Late August through September was excessively warm and dry, with negative effects on fall crops.
With that in mind I will look at each crop to consider how the various factors may have affected the yield I obtained in 2013 compared to past years.
Beets. The yield I obtained is somewhat higher in 2013 than in 2011 while I harvested the same number of sugar beets per unit area this year as 2011 according to my records. That suggests that soil re-mineralization may have had a mild positive effect on this low-demand crop.
For ‘Cylindra’ beets, even though I used row planting, I got about the same number of beets as I would have if I had used HTGMV’s triangular planting pattern and suggested spacing. Planting in rows is much easier so I plan to continue to do so. The yield of ‘Cylindra’ may have benefitted most from growing the beets more thickly as I harvested about three times as many beets this year per unit of space, and the yield increased by a factor of three as well.
Bok choy. Table 1 shows that I planted bok choy about three weeks later in 2013 than in the previous best year. Because the St. Louis area has very short springs followed by hot summers, spring-planted crops have little leeway in planting date to obtain the best yield. The reduction of yield this year may be due to late planting and perhaps stunted growth resulting from the three months between seed sowing and transplanting versus the two months generally recommended and done in the best-yielding year.
Broccoli. Another crop I planted late and after too long in the seedling stage, which may have lowered yield in 2013. However, varietal differences in yield cannot be ruled out as a possible factor in the results in Table 2. To learn this I would need to grow both broccolis the same year with all else held constant. Note that the yield of ‘Nutri-Bud’ broccoli increased by a factor of 3 in 2013 versus 2012, despite being planted late in 2013 versus at the correct time in 2012. Since broccoli is a high demand crop that would be expected to show a significant increase in yield with proper fertilization, this seems to be evidence of the beneficial effect of soil re-mineralization on its yield.
Cabbage. The 2013 yield of ‘Early Jersey Wakefield’ cabbage is strong evidence of the deleterious effect of late planting, as I have planted this variety at the same distance for many years. Interestingly, ‘Golden Acre’ cabbage had double the yield of ‘Early Jersey Wakefield’ despite the planting distance being larger and other factors the same. I will grow both cabbages again next year.
Carrot. I harvested about twice the number of carrots per unit area in 2013 as in 2012, so the increase in yield in 2013 may be attributable to that rather than soil re-mineralization, as carrots are a low-demand vegetable.
Eggplant. Eggplants are a medium-demand vegetable so one might expect that they would have yielded better in 2013 than in past years. Comparing 2013’s two varieties to the ‘White’ eggplant of 2012, this year’s plants underperformed. However, the ‘White’ eggplant of Table 1 was a purchased plant, possibly a higher-yielding variety, as opposed to the two open-pollinated varieties I grew from seed in 2013. The purchased eggplant was also much larger than my homegrown seedlings, which may have allowed it to start yielding earlier. Still, of the several other open-pollinated varieties of eggplants I have grown in the past, none yielded as well as this year’s two varieties. Thus soil re-mineralization may have had some benefit on yield, especially considering that ‘Black Beauty’ has a reputation for low yields.
Since our hot, long summers should favor eggplants I have wondered why my eggplants have not performed closer to the mid-range yield listed in HTGMV. A close perusal of the Master Charts suggests that I may have been overcrowding them. The suggested spacing in HTGMV amounts to about two square feet of space per plant while I have been allotting them one square foot of space per plant. That fact, and the fact that the 2013 eggplants were crowded up against much taller tomatoes and may have suffered from excess shading and competition from them, may explain the rather low yields this year. A good test of this possibility would be to plant some of the 2014 plants at one plant per square foot and others at one plant per two square feet and monitor the yield at each spacing. I will also ensure they are not shaded by taller plants.
Garlic, leeks, and onions. The beds with the garlic, leeks, and onions were planted before the soil test results arrived, thus they did not receive the mix designed to re-mineralize the soil. In addition, all of these vegetables were planted at a larger planting distance than in the years with the highest yields resulting in fewer plants per unit area, and the bulb onions were planted late in 2013. Thus I expected none of these to match the highest past yields, and none of them did. I planted next year’s garlic and potato onion crops at a 6 inch spacing, hypothesizing that the combination of soil re-mineralization and a closer spacing will result in higher yields in 2014 compared to 2013.
Lettuces. ‘Anuenue’ yielded slightly better in 2013 than its previous best year, ‘Bronze Arrow’ and ‘Pirat’ worse. ‘Anuenue’ is a later-maturing, long-standing lettuce developed for hot climates. That may be why it did better than the other two in a year in which they were planted later than is recommended for Missouri.
Peas and peanuts. The peas and peanuts were planted in a bed that was prepared for planting before the soil test results arrived, thus it did not receive the soil re-mineralization mix. In addition, the peas showed poor germination, perhaps because I did not pre-sprout them before planting. (I did not pre-sprout in 2012 either but that was a much warmer spring than 2013, reducing rotting due to cold soil.) Also, the peas sprawled too much due to my not supporting them. Thus the low yield in 2013 was not a surprise. I was gratified that the peanuts yielded as well as they did since it was the first year I grew them. I will grow them again.
Peppers. I expected pepper yields to be higher than they were because peppers are a high demand crop that would likely benefit from soil re-mineralization. However, the ‘Carolina Wonder’ and ‘World Beater’ plants suffered from considerable shading by taller crops on either side of them, while the ‘Italian Frying’ plants were less shaded. Its lower yield than in the best previous year may be partially attributable to being planted three weeks later and partially attributable to the shading it experienced. See below, however, for a different and noticeably positive effect of soil re-mineralization on the pepper crop.
Potatoes. The spacing used for the highest-yielding potato crop is equivalent to that recommended in HTGMV and is far closer than the spacing I use now, thus I did not expect to match the best past yield even if the plants responded positively to re-mineralization. I use the much wider spacing because of the sprawling nature of potato plants: it keeps them from shading nearby crops, and I can hill up the widely spaced plants. The result of note this year was how much better the yield of ‘Elba’ was than ‘German Butterball’. ‘German Butterball’ yielded 7.6 times the planted weight while ‘Elba’ yielded 15 times the planted weight! It also produced a few large potatoes per plant that were easy to harvest and it tasted delicious. I’ll be planting ‘Elba’ from now on.
Winter radishes and turnips. These seem to have suffered from excessively hot fall conditions and from my not thinning and weeding them in a timely manner. I planted them in the area where cabbage and broccoli had grown without adding more fertilizer, so there may have not been adequate nutrition left for them to fulfill their potential.
Squash. The low yield of ‘Bennings Green Tint’ doesn’t reveal that this was the first year after a number of years of trying that I got any of this squash at all. The very much higher yield of zucchini in 2013 is likely due to a combination of soil re-mineralization (it is a medium demand crop) and a variety well suited to my conditions. At first glance the planting date for winter squash appears very late for this area and suggests reduced yields versus HTGMV’s possible yields, but past experience has shown that earlier planting results in much less squash due to squash bug attacks killing the vines. However, I may try earlier planting again since other pest problems seemed less this year, a point covered more below. The ‘Sweet Meat’ squash yielded better in 2013, but the later planting for ‘Butternut’ may have had a negative effect on its yield.
Sweet potatoes. I planted the equivalent of 40 plants per 100 square feet of ‘Ivis White Cream’ in 2008 while I planted the equivalent of 25 plants per 100 square feet of ‘O’Henry’ this year, yet the yield of ‘O’Henry’ was not much below that of ‘Ivis White Cream’. Given this, ‘O’Henry’ made a better showing. I do not know if this is because ‘O’Henry’ was planted about a month earlier, because the larger spacing meant it had less competition, because it is a higher-yielding variety, or because of the soil re-mineralization (sweet potatoes are a medium demand crop). I prefer to plant at the 48-inch between-row distance because it is easier to dig out the crop. But I might alter the plant spacing across the bed in 2014 and keep track of the yields of the different parts of the bed to get a better idea of the optimum spacing for ‘O’Henry’.
Tomatoes. While I did not see much difference in yield for ‘Arkansas Traveler’ from 2012 to 2013, yields were much lower in the six preceding years. I had trouble with disease affecting the plants in the wet years of 2008-2011 while 2012 was very dry, which I suspect greatly reduced disease problems that year and thus boosted yield. Compared to 2012, 2013 was a wet year so I was pleased that this tomato yielded so well, close to its best. ‘Hungarian Italian Paste’ yielded about twice as much in 2012 but it also yielded less in the six years preceding 2012 than it did in 2013.
Overall, therefore, where the effect of soil re-mineralization could be separated from other changes from year to year, the effect seems to be positive. However, I’ll need to pay more attention to plant spacing, planting dates, and varieties grown in future years to better answer this question.
Question #3: effect of re-mineralization on flavor or pest or disease resistance
The most noticeable change in flavor was in the ‘Early Jersey Wakefield’ cabbage. My notes say that this year’s crop was very sweet with none of the off-flavor that cabbage sometimes gets. I cannot attribute that entirely to soil re-mineralization because the weather was cooler and wetter than usual while it was growing, but a balanced soil may have contributed. ‘Anuenue’ lettuce also had excellent flavor with no bitterness whatsoever and the heads were very dense and crispy. I wasn’t as impressed with it in previous years, but the Fedco seed catalog does list these as varietal attributes. It may be that soil re-mineralization allowed it to reach its full potential as lettuce is a medium demand crop. At any rate I will grow ‘Anuenue’ again. ‘Bronze Arrow’ lettuce also seemed less bitter this year, but ‘Pirat’ lettuce seemed more bitter and I may look for a replacement for it. Otherwise I noticed no flavor differences in those crops whose taste I know well.
While I had hypothesized that I might have less trouble with harlequin bugs and squash bugs, I did not predict that cabbage moths would be less trouble, which turned out to be the case and was most welcome. I didn’t notice any harlequin bug problems as I sometimes have with cabbage-family crops after midsummer. The squash bugs did eventually show up but by the time they did, the squash had already set fruits. I think I had some squash borers also but they did not seem to be much of a problem. Overall pests seemed to be less of a problem in 2013, which I attribute to the re-mineralized soil since I know of no other way to explain this.
Over the past few years I have been plagued with one or more diseases affecting the pepper and tomato crops. This year every single pepper plant survived the entire season! Although yields were lower than the best I’ve gotten, they were improved over those of the past few years. All of the tomato plants of the two varieties in Tables 1 and 2 also survived the season. I think this can be attributed to soil re-mineralization since the wet conditions in May and June would have promoted disease as noted in previous wet years.
Question #2: effect of soil re-mineralization on post-season mineral levels
After receiving the post-season soil test results and comparing them to the pre-season results, and while re-reading Solomon’s The Intelligent Gardener, I realized that I need more time to ponder what the soil told me this season. It’s a complex (and fascinating!) topic that deserves a post of its own. It may be awhile before I get to that post since I will likely write the post on the questions I’m asking the garden to answer in 2014 first. But I do plan to re-balance soil minerals in 2014 since wherever I could discern its effect, it was positive.
