Is it the nitrogen content that makes beet juice beneficial to battling hypertension? Can you grow a beet crop without nitrogen fertilizer? An interesting project involving beets, high blood pressure, and a harvest with the lowest nitrogen content possible. By the end of this article, you might well be wondering about the possibilities of adjusting fertilization for certain crops to produce natural medicine.
My old university contacted me 3 months ago about growing some beetroots for them. An easy task by no stretch of the imagination, but not when they want beetroots with as little nitrate as possible! The reason for this is the potential medicinal effects of beetroot juice on people with high blood pressure (hypertension). Early research has shown that beetroot juice reduced blood pressure in people who exhibit chronic high blood pressure, and therefore, may have an effect on reducing incidents of cardiovascular disease.
The Deep Science Part
Dietary nitrates, like those obtained from eating beetroots, could be a source of the biological messenger nitric oxide, which tells the endothelium of arteries to trigger smooth muscle and vasodilation, which increases blood flow… This basically means the body’s cells get increased blood flow, and therefore, more oxygen. For this reason (increased oxygen to the muscles) cyclists have also been exploring beetroot juice to improve their speeds and times.
The Growing
I set up 24 pots in a 8’ x 4’ grow tent, with 12 in Gold Label soil, and 12 in Plagron coco. The beetroots were all from F1 Bolt Hardy type seed, and the seedlings were all transplanted into bigger 3-quart pots, and finally into taller 3-gallon pots. On the 12 in soil, I used Hydrotops Solo Grow and Bloom on 6, and Just Bloom on 6. During the first 4 weeks of growth the soil grow was used at a dose of 1.5 ml per litre, which gave me an EC of 0.8, this was increased to 2ml per litre in weeks 5-6 which gave an EC of 1.2. I then lowered the dose of the soil grow to 1 ml per litre in week 7-8, as I started using the soil bloom at a dose of 3ml per litre which gave me an EC of 1.5. In the final 4 weeks I stopped using the soil grow completely, and just used soil bloom at a rate of 5 ml per litre, which gave an EC of 1.8 maximum.
In the coco, I used the Hydrotops coco nutrient, watered 6 on coco grow and bloom, which is a 2-part nutrient with A+B grow, and A+B Bloom. The other 6 in this group were grown using only coco bloom. I followed a similar pattern as the soil grow so will not repeat here to avoid repetition. The reason for splitting the beetroots into 4 groups was twofold; it would be interesting to see the effect of minimal nitrogen on developing beetroots in soil and coco, but also to see if the lack of nitrogen helped in our test to produce a beetroot with low levels of nitrates. The test was carried out over 3 months, and the results were quite interesting.
The Results
The soil-grown beetroots developed nicely, even those grown on Just Bloom, although they were significantly smaller. The coco beetroots on Grow and Bloom also did well, but the beetroots on just bloom feed did very poorly, developed deep purple leaves, and what can only be described as a pebble of a beetroot.
Discussion
The results have pointed out something that was quite interesting and should make you think about your medium of choice in the future. Soil is a very forgiving medium to work with, even when I technically ‘messed up’ by just watering bloom feed, it produced an edible crop, although much smaller. Coco is a much less forgiving medium, and when stressed will punish the grower, but if treated well will reward with great yields and good flavor. However, something I would look into before the next round of growing is to measure the background nitrogen levels of the soil, which would make the tests much more accurate, and help in developing the final technique for growing low nitrate level beetroots. The beetroots are now in a lab being analyzed by the university, and I should have some results on the nitrate levels shortly. From these results, we can adapt the growing methods, and improve on our quest to grow a low nitrate beetroot. I have a few tricks up my sleeve to inhibit nitrogen uptake, but most of them will definitely impact the plant negatively in one way or another- so this trial could last for the foreseeable future. I will keep you all updated when we come up with the solution.
Further Reading:
- Lundberg, J.O.; Carlström, M.; Larsen, F.J.; Weitzberg, E. (2011). “Roles of dietary inorganic nitrate in cardiovascular health and disease”. Cardiovasc Res 89 (3): 525–32.
- Hobbs, D. A.; Kaffa, N.; George, T. W.; Methven, L.; Lovegrove, J. A. (2012). “Blood pressure-lowering effects of beetroot juice and novel beetroot-enriched bread products in normotensive male subjects”. British Journal of Nutrition 108 (11): 2066–2074.
This article written by Stephen Brookes from NPK Technology in Liverpool is republished here from Issue 6 of Garden Culture Magazine. It originally appeared under the title, Just Beet It!