Cabbages happily growing in early June 2019
If you have been reading my blog for awhile, you will know that I grow a vegetable garden and that I strive to grow as high a yield as possible of delicious vegetables in a limited space, in the most sustainable manner possible. Toward this goal, each year I develop one or more questions to ask the garden to answer through applying the scientific method to my gardening practice. The big question that I asked my garden to answer in 2019 is if the urine that I produce as a byproduct of being alive can provide sufficient nitrogen to grow dent corn in place of using cottonseed meal as I had been doing. And I’ll get to what the garden told me in due time.
As usual, the garden also told me the answers to some other questions that I hadn’t asked. So let’s start by examining the weather during the 2019 growing season to learn how the weather affected the vegetable garden. Then we’ll examine the data that I collected on yield, which is one of the ways the garden communicates with me, to learn how the garden responded to the weather and to the test that I set up. Finally, I’ll share observations I made on taste and pest issues with some crops for my own use and for those of you who also grow these crops in your gardens.
I can describe the weather in 2019 in one word: wet. St. Louis has not experienced such a consistent excess of rain across the growing season since 1993 – and as in 1993, the rivers flooded in response. The Mississippi River at St. Louis was at or above flood stage for 127 straight days from late March through late July!
Here’s how much rain the garden received in each month of the growing season compared to the average for each month as reported by the St. Louis NWS office. Because freezes in March and November would split the plastic rain gauge I use, I reported the value measured at the official site for St. Louis for these two months. The values for the other months are totals of what I measured in my rain gauge during rain events in that month.
Notice, first, that the only month in which our garden received significantly less than average rainfall was September. Second, note the astonishingly large total rainfall in August. Almost half of this, at least 5.5 inches of rain, occurred in a single storm event on August 12! This was about double what the official recording station received during the same time period. Nor was this our only rain event of this size; 5.0 inches of July’s rain fell in a single storm event on July 22, and this was about 50% more than the official recording station received.
Given this much rain, I feared that the excessive rainfall and accompanying humidity would reduce yields in general due to waterlogged soil. In fact, while the yields of some crops were lowered, other crops yielded as well as or better than they usually do. This suggests that while what I considered excessive rainfall may have had a negative effect on some crops, other crops do well, perhaps even better, with very moist soil. I’ll discuss this more in the reports on individual crops.
Concerning temperatures, spring tended to be cool, with the last frost occurring on April 15. A period of particularly cool weather occurred from May 9 to 14, when I was planting some of the summer crops. Seeds that I planted during this time failed to germinate and needed to be re-seeded. Summer temperatures averaged to near normal while September proved to be much warmer than normal, as well as drier. October averaged a little cooler than normal, but the usual wide autumnal temperature swings produced an early frost on October 12 and a hard freeze of 25F on November 1, for a growing season of 180 days, two or three weeks less than average. Based on temperature, spring crops would yield about their average, summer crops would yield better than average (because our average summer weather tends to be hotter than most of the crops other than corn prefer), and fall crops would do poorly. Most crops fell roughly in line with these expectations, with notable exceptions being peas, beans, eggplants, cabbage, winter squash, and zucchini, all of which yielded less well than I would have expected.
Below you’ll find the data for each crop that I grew in 2019.
Rather than discuss each crop or group of crops in detail, I’ll only mention those that answered particular questions that I asked the garden or that the garden asked and answered. If any reader has a question that you’d like answered about any of the crops, please feel free to post it in a comment and I will respond by the time I put up the next post.
First, the muskmelons. I spent years trying to grow ripe muskmelons on the ground or on vertical trellises, with no success. Other area gardeners as well as farmers grow them, however, so I decided to try them once again. In 2019 I grew them a new way, on an A-frame trellis, thinning to two plants on that trellis.
Those two plants produced eight ripe melons over a month long span! They were planted on the same day as the winter squash, but the melons performed much better than the winter squash and the zucchini planted about 10 days later. The latter two grew on the ground compared to the trellised melons. I wonder if getting the melons off the ground may have been key to their better growth and yield during the excessive rain and humidity of the summer of 2019. Also, melons are a moister crop than winter squash, so I think melons would benefit more from consistently moist soil than winter squash. Given how well the melons did in such a wet growing season, I plan to favor them with any irrigation I need to do during future growing seasons.
Second, the sweet peppers and tomatoes. Both varieties of sweet peppers yielded as well as they did in the best previous year, 2015. Both 2015 and 2019 featured excessive rainfall; 2015 was a little warmer than usual, 2019 a little cooler. I conclude that sweet peppers, like melons, benefit from consistently moist soil; I will also favor them when irrigating in future years. Also, while the ‘Purple Beauty’ bell peppers yielded very well, I found them to not have as good a flavor as ‘World Beater’ when ripe. As for the tomatoes, their yields were higher than I reported because we were out of town during the couple of weeks when they first ripen. I gave a friend permission to harvest all the tomatoes that ripened while we were away from home. While she didn’t weigh them, she reported that she harvested many tomatoes! Still, I’ve noticed in past years that tomatoes suffer during warm, wet conditions, so they probably didn’t yield as well as usual in 2019.
Third, the kale and collards I tried to keep going through the summer. In past years harlequin bugs attacked cabbage-family crops like kale and collards that I left growing after late July, so I got in the habit of removing them then, a few weeks before planting the autumn crops. In 2019 the weather was cool and moist enough I decided to leave the kale and collards in the ground. Wrong move. By the time I planted the autumn crops, the kale and collards were being attacked and eaten by a caterpillar that I could not identify. Sometime in October I realized I should have taken some of the caterpillars to the Missouri Extension Service desk at the Missouri Botanical Garden so their experts could identify them, which may have helped me learn how to control them. By that time the caterpillars were gone … but before then they had moved over to the seedlings and fed freely on them, setting them back. Add that to the hot, dry conditions in September that these plants dislike and none of the autumn cabbage-family crops did well. May I learn this lesson for good this time.
The kale looked great on June 24, before the caterpillars attacked
Fourth, the dent corn. I wanted to know if I could substitute my urine for the cottonseed meal that I had used before as a source of nitrogen, so I designed an experiment for the garden to provide me with an answer. Because of the excessive rain and cool weather in May, I had to delay planting the corn until the beginning of June. Then a too-short dry spell meant I could only plant two beds on the same day. So I made a change in the experimental plan. As in the original plan, I used cottonseed meal on Bed 5 (the control) and urine in place of cottonseed meal on Bed 4, keeping the other added amendments the same (the experiment). For Bed 6, I used cottonseed meal and the same amendments, so in this respect it was treated the same as the control bed, except that it was planted three days later. The later planting made it an experimental bed as well, with the variable being the planting date.
You will notice that the results are the same for all three beds (the kitchen scales I use to weigh the crops are precise to two significant digits) and better than the results from 2017, a much drier growing season than 2019. I conclude that urine was successful in replacing cottonseed meal as a source of nitrogen, the significance of which I’ll discuss in the next post. I also conclude that corn is another crop that benefits from consistently moist soil.
With that, I will return you to whatever else you need to do, and I will return to completing the 2020 garden design. When next we meet, I’ll let you in on what I plan to ask the garden in 2020.