Friday, September 12, 2014

Summer 2014 Oakleaf Trial


Summer 2014 Oakleaf Trial
Natalie Bumgarner, PHD


Methods and Management

Seeding was done by hand into pre-moistened 1” x 1” x 1 ½” cubes of three different media (Grodan 200 ct rockwool, Oasis XL 162, and GrowTech 162). Seeds were germinated in clear water in seeding trays, and were transferred to the nursery and nutrient solution 3 to 5 days after seeding. Seedlings were produced in flowing nutrient solution in the nursery for an additional 10 to 12 days before transplanting. Due to the season, no supplemental lighting was provided during the seedling phase. After transplanting, plants were grown out in the channels for 25 to 28 days until harvest. The nutrient solution was continually cycled through the Fertroller where automatic pH and EC adjustments met programmed solution set points. The pH was maintained at 5.8 by the addition of dilute sulfuric acid. EC was maintained at 1.7 by the addition of concentrated fertilizer solution and source water. Tank changes were carried out every two weeks.

Timing and Conditions

Biomass Yield



Media Impacts

Some comments on the trial


Looking over the environmental and yield data, there are some interesting points and items that I would like to pull out and discuss a bit.

  • I haven’t really focused often on the environmental data in previous blogs- mostly saying that through a four run trial, there was quite a bit of environmental variability. This trial, though, I want to point out that over a four month period in northeastern OH, we probably won’t find many data sets with this similar a set of conditions. Carbon dioxide stayed quite consistent and especially across the last three runs, the temperature and light were also quite similar. Humidity did increase under warmer summer conditions as the wet wall ran for longer periods of time to reach cooling set points. Due to similar environmental conditions, we also followed fairly consistent transplant and harvest schedules through the four runs I comment on the environmental conditions because it is clear that some variability still exists in crop growth rates and final yield even with reasonably similar temperature and light conditions (similar for a greenhouse meaning outside a growth chamber, etc.).
  • Having discussed the reasonably similar environments, this leads to some serious questions about why there was so much variability in the weights reported in earlier tables. One key reason is that we experienced some seed quality and germination issues. This was most clear in the Panisse and Oscarde cultivars where germination was inconsistent in the first three runs (we switched to a new seed lot in the 4th run). This led to uneven growth or not even having enough seedlings to provide the 15 plants of each cultivar in each media. A glance at the standard deviations in the previous slides illustrates that these two cultivars were generally more variable than the other three. Germination and plant stand likely had a strong influence on those deviations.
  • The third and final thing I want to talk about is related to the other two points of discussion. The use of three different growing media had some interesting general impacts. I inserted runs 1 and 4 into the above table because they represent the most complete data sets. Overall, for the Kireve, Rouxai, and Rutiali cultivars, peat cubes tended to show the potential for yield increases. These trends were not repeated and were in some cases reversed in the cultivars where germination and plant stand were less consistent (Panisse and Oscarde). Does that suggest that peat performs differently in some cultivars over others? I cannot say that this is not the case, but I can put forth another idea. It may be that in seed lots and cultivars with strong vigor and rapid germination, peat can be an asset to seedling production and plant growth. However, rockwool and/or oasis may be providing better environments for germination and early growth in less high quality seeds. More investigation is certainly needed as there is definitely room for improvement in our seedling production, and further work will help us better understand whether we are dealing with a seed, media, or environmental issue.
Plant Images

Kireve- Run 4

Oscarde- Run 4

Panisse- Run 4

Rutilai- Run 4


Rouxai- Run 4

Monday, August 4, 2014

Branching out with Brassicas - Summer trial in NFT production in Ohio


Branching out with Brassicas
Summer trial in NFT production in Ohio
Natalie Bumgarner, PHD


Introduction

In the greenhouses that I visit and crops I discuss with growers, it is clear that lettuce still fills a majority of plant spaces in the NFT system. However, we field an increasing number of questions about the many other leafy crop possibilities. Many of the other leafy options are in the Brassica family - cabbage cousins, essentially. These include kale, mustard, mizuna, and pac choi most commonly.


These options present growers a chance to diversify to attract new customers as well as provide more product to existing customers. One of the challenges with any new crop is understanding its production capacity to assist in pricing and tailoring production to anticipated demand. Also, there is the potential for higher light and temperature to negatively impact quality in the summer as is the case for some lettuce and other leafy crops. This trial was designed to evaluate a selection of Brassica crops as well as amaranth (not a Brassica, by the way) under summer conditions. Rather than extensively trialing multiple cultivars of the same crop, the goal was to evaluate production capacity and crop quality of a selection of alternative leafy crop
options to lay a broad foundation for future work.

Methods and Management
Seeding was done by hand into pre-moistened cubes. Three media were compared in this trial- rockwool (25 x 40 mm), Oasis (162 count Horticube XL), and a peat media (162 count, Grow-Tech). Seeds were germinated in clear water in seeding trays, and were transferred to the nursery and nutrient solution 3 to 5 days after seeding. Seedlings were produced in flowing nutrient solution in the nursery for an additional week to two weeks before transplanting (no supplemental lighting was provided during the seedling phase). After transplanting, plants were grown out in the channel until harvest. The nutrient solution was continually cycled through the Fertroller where automatic pH and EC adjustments met programmed solution set points. The pH was maintained at 5.8 by the addition of dilute sulfuric acid. EC was maintained at 1.7 to 1.8 by the addition of concentrated fertilizer solution and source water.

* This trial measured single harvest yields to produce the most accurate and comparable yield totals. However, some growers may harvest single leaves or leaflets from kale or amaranth plants. This could increase the total yield per plant but require additional time in the channel and quite honestly make comparisons much more challenging.



Timing and Conditions


Biomass Yield
* Amaranth was seeded with multiple seeds per cube as is typical in production, but this increased the yield variability.

Some thoughts on the trial

After considering these trials, there are a few things that I would like to bring up for discussion.

  • First, I should report that there were very few quality issues with any of these crops in these trials. They grew through the OH spring and summer conditions quite well with no losses or issues to speak of.
  • Second, and most clear in the data, we can see that the yield potential of these crops is wide ranging. That is really an understatement. In fact, we had to use two different scales to weigh these trials. Besides our scale challenge, there are two key grower impacts. One is the fact that timing of transplanting and harvest really should be varied. The kale maybe could have been grown a bit longer and the WinWin Choi should have been harvested earlier for highest quality. The other important point is that it will be important for any grower going into sales with such crops to do a few trials before setting prices. We can often count on bibb lettuce to finish out at predictable weights at predictable times, so prices can be set and costs calculated simply. When selling and pricing kale, pac choi and the like, be aware that yields and therefore input costs per weight of produce vary. Don’t undersell yourself early in the process of growing a new crop.
  • Thirdly, the impact of our different growing media was not clear in these trials. This is certainly my least favorite point as unclear results frustrate every researcher. In looking at the yield trends between the two runs, the differences (or lack thereof) between rockwool, oasis, and the Grow-Tech cubes were not consistent. In run 1, the peat cubes tended to perform better while that was not seen in run 2. Environmental conditions were reasonably consistent in these two trials, so that is unlikely to be the primary cause for these inconsistencies. I am hesitant to draw too strong a conclusion about this on early trials, but I will say that it may be differences in germination speed, moisture content (and therefore fertility), temperature and the like early in crop growth that led to these variations. We generally deal with pelleted lettuce seed that produces very consistent germination and early growth. Because these Brassica crops are not bred for controlled environment production, their response to small differences in conditions may not be as well understood at this point in time. More focus on the seedling aspect may well be needed.
Notice the difference in germination rate and seedling size between the five crops in this trial. Tiny amaranth seedlings are in the back of the tray.
Plant Images from Run 1

Toscano Kale- At harvest (44 days after seeding)




























Red Giant Mustard- 44 days after seeding




Red Choi- 44 days after seeding




















WinWin Choi- 44 days after seeding






















Red Leaf Amaranth- 44 days after seeding

















Thursday, June 12, 2014

2014 Tomato Trials- Summer Sneak Peak


2014 Tomato Trials- Summer Sneak Peak
Natalie Bumgarner, PHD

Trial Overview

For many of the producers that we serve, beefsteak tomatoes are a large majority of their production. However, trends in consumption and competition are increasing interest in specialty cultivars. From demand for farm to school salad bar items to farmers market mixed baskets, there are a range of options for small fruited and colored tomatoes. While visual interest and taste are critical in these cultivars, it is essential that production be adequate and relatively consistent over the season. These two questions are the reason behind this trial. Exhaustive yield data is not possible on the scale that we trial in our test greenhouse, but early evaluation is essential to begin to make suggestions for growers. So, this evaluation was carried out on small plots of fifteen cultivars to assess plant production throughout the season. These are preliminary trials to determine what cultivars to trial more extensively in the future.






















Plant Management

•All ungrafted seedlings transplanted from 1.5” rockwool cubes into perlite filled Bato buckets
•Plant density was 4 ft2 per plant or 2.7 plants/m2
•Began feeding seedlings at 1.5 mS/cm EC and increased feed to 2.2-2.4 mS/cm as mature plants
•Target leach ECs were 0.4-0.6 above feed ECs (2.6 to 3.0 mS/cm)

Italia- Roma

























Itaca- Roma

























Prunus- Roma











Colored Plums


tiger plum
small pink








Dasher
























0603









72-163RZ


Zebrino









Cantina Purple









Vacetto






Orange










DRC-564