Learning clues after the harvest is vital to building upon gardening knowledge and success.
This photo shows some recently harvested broccoli from one of my neighbor's veggie beds. Since I have also seen a couple stalks of similar nature at the garden, it may be a timely post.
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| Hollow Heart in Broccoli! |
What can we learn about the plant and preventing future problems by viewing what remains after harvesting the central head?
Let's take a closer look at the photo to the right and see...
If you look at the center of the harvested central stem, you will notice a hole in the middle or a condition known as "Hollow Heart" in broccoli.
While the condition will not affect any of the flavors, depending on the circumstances, it will substantially reduce the overall health of the plant when desiring that delicious side shoot production. In addition, depending on how far up into the head the hollow heart goes, storage ability of the broccoli will decline.
If you were growing for market, this is a serious problem as it is considered a defect that reduces the marketability of your crop. For the home gardener, it does not present too much of a problem if you take corrective measures to protect future plantings. However, this year, you may not be able to obtain the side shoot production you were hoping for as hollow heart does decrease the health and yield of your plants.
Many gardeners point to hollow heart as just a boron deficiency. In reality, it is most often caused by a few factors. It can be any one of the following or a combination of several.
1) The level of boron in your soil is running low and needs rectified.
2) The plants are receiving too much of a good thing when it comes to feeding them nitrogen or supplying them water.
3) The plant rate of growth is too fast. In other words, the plant is growing faster than it can readily uptake the nutrients provided.
So, now I know there is a problem, what do I do...?
First - Correctly identify the source of your misfortune. The process of adding unnecessary elements to the soil, such as boron, can create an environment of toxicity to both plants and soil microbial life. The potential side effects of over supplying boron would vary from crop to crop.
To try to determine the root cause we did a distilled water soil test and found this gardener's nutrients on the high side. In the absence of any other signs and symptoms common to a boron deficiency, our diagnosis is then two, three, or a combination of both above. Turns out this gardener added an entire box of EB Stone Starter Fertilizer to their raised bed at planting time and a little blood and bone in the planting hole for good measure. This knowledge confirms that we are right track with our line of thinking. The correct rate of EB Stone Starter for 32 square feet is only 2 1/2 cups. The entire box would have been close to triple the amount recommended, if not more. In addition, blood meal is a very high nitrogen source and while organic, excessive amounts will cause some trouble as seen.
Final Diagnosis: "Hollow Heart" due to excessive use of over-fertilization.
Recommendation: Remove the plants since the overall health is compromised for side shoot production. The hollow area in the stem will fill with water and rot the plant over time. In addition, aside from the plant maybe containing unsafe levels of nutrients based on our findings, it will attract many undesirable insects to the garden as the stem deteriorates. The soil will need retesting in the spring so we can take the necessary steps to rectify and the gardener's fertilization habits need corrected for all future plantings.
Side-note: This gardener recut the stems at the proper angle for side shoot production and placed duct tape over the hole to prevent water from entering. During the heavy rain this week, he placed a sandwich bag and rubber band for added protection. I am cracking up as it is amazing what we will try in the garden but the experiment is to see if the hollow heart passes on to the side shoots as well. A very worthy experiment. If so, the plant will be pulled. If not, he told me to look over the fence at night, as he may just be glowing, grin!
Green Meadows Healthy Garden Tip:
Boron is a micronutrient essential to the structure of plant growth and development above ground, especially on those plants with robust stems. It is actually one of the more common nutrient deficiencies to show up. However, in excess, it can present a host of other problems. Most often boron levels are kept in balance when you rejuvenate the soil with good quality compost. It depletes from the soil quite slowly over time.
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| Hollow Heart at Green Meadows last fall! |
Many gardeners tend to reach right for the 20 Mule Team Borax when they see the hollow stem as it is inexpensive, readily found as an organic solution on-line, and an easy fix for the condition. However, this isn't always the best move unless you truly have a deficiency in your soil. Examine your plants and garden further to prevent excess fertilization and the common problems that an abundance of nutrients can also cause.
If your plants present with a hollow stem, look closely at the core to determine a basis for diagnosis. What symptoms and signs does the plant have? Is the hollow area the same color as the rest of the inner stem, similar to the first photo above, or is it brown, calloused, and off in texture and color? What does the broccoli head look like? Is there some browning on the curds? Do you notice anything off with any of the other plants in your garden? How did you prep your bed and what are you using as your fertilization practice?
If a boron deficiency is truly present, you will notice more than just a hollow stem depicted in the photographs. This gardener was about to add borax inappropriately. The disorder in either of these photos is more likely caused from improper fertilization based on our research and findings.
If you do run into trouble and need to add these types of elements to the soil, an inexpensive soil test from the extension office can verify your findings and provide the proper recommendations to manage the issue. Boron levels are either replenished through proper soil management and compost or with the addition of 20 Mule Team Borax.
For those who may need the proper recommendations, a link is below for your convenience. The article has some very nice information on the uses of Borax in the organic home garden. Please keep in mind that even though something is organic it does not mean that it isn't detrimental to the soil and plants if used in abundance.
http://homeguides.sfgate.com/role-20-mule-team-borax-organic-gardening-74730.html - link to an article written by a former UGA Extension Office Master Gardener Coordinator.
Happy Gardening,
Denise, Beds 25 & 29
