Is Soil-grown produce as nutritious as hydroponically-grown veggies and greens?
Like with everything else, Hydroponics has its fair mix of promoters and detractors. Many pin it down to a new fad or an unnatural way of growing, while others are incredibly upbeat, calling it the future of Agriculture. In today’s blog, we will touch upon an equally important and pertinent topic regarding Hydroponics – Nutrition with comparison to soil grown produce.
But before that, it’s important for us to go through some aspects of Hydroponic farming:
· It is a scientific and calculated method of growing produce.
· It takes into account the specific requirements of each plant.
· It allows excellent control over the nutrition profile of the plant.
· It eliminates a large number of pests and thus eliminates the need for using dangerous pesticides, herbicides and chemicals.
The nutrient mix provided to the plant: Let us compare the produce grown inorganically in soil vs. the one grown in Hydroponics.
In both these cases, the primary fertilizer inputs applied to the plants are similar. They mostly differ in their form, solid vs. liquid, but the underlying compounds/minerals/elements are the same. As such, there is no significant difference in the fertilizer inputs used in soil-based growing vs. Hydroponic growing. So, logically there should be no difference in the nutritional quality of hydroponic produce vs. soil-grown produce.
Yet, subtle differences can still appear because of the following two reasons:-
1. Percolation of nutrients applied – Fertilizer usage in the soil does not support the principal of re-circulation. An overwhelming majority of soil-based agriculture in India is dependent upon rain or uses flood irrigation methods by extracting groundwater through bore-wells. An inherent drawback of such irrigation practices is that a large amount of fertilizer seeps through the soil and get mixed into the groundwater or nearby water bodies. The pollution of natural water resources is one of the biggest banes of excessive use of fertilizers. In traditional farming methods, though a farmer can control which and how much nutrient is given to the plant, once cannot possibly control the extent to which it remains available for intake by the plant. The nutritional science in Hydroponics, on the other hand, works on the principle of re-circulation. In Hydroponics, the nutrient-rich water is recirculated back through the plant roots repeatedly. This re-circulation process helps in two ways; one, it ensures minimal wastage of nutrients. Second, the plant roots have nutrients available to them at all times. Due to this reason, a Hydroponically-grown plant has a better nutritional profile as compared to soil-grown plants
2. Soil Condition & Profile – In the case of soil-grown plants, apart from the nutrients added by the farmer, the soil itself may have many trace elements and nutrients (some of which may be beneficial and some may be harmful). However, in the case of Hydroponics, unless the farmer adds a nutrient externally, the plant may never get that nutrient. Due to this reason, the soil-grown produce may have a higher amount of some elements as compared to their hydroponically grown counterparts.
In an average case scenario, hydroponically grown produce will have a slightly better nutrition profile as compared to soil-grown produce. The same has been verified time and again by different farmers and experts from agri-industries who grow medicinal and aromatic plants. When they grow these plants using Hydroponics, the concentration of active ingredient/oil content is much higher as compared to soil-grown plants. The same should hold for nutrients.
Post-harvest nutrient loss in the plant: The moment a plant is harvested, it begins to lose nutrients. Higher the temperature more is the loss. What that means for you as a consumer is that if your food is grown in far off places and takes a long time transiting through the supply chain, it will have little nutrients left by the time you consume it. So, to get the same amount of nutrients as you expect you are getting from eating a single bowl of Spinach, you may as well need to eat two.
The point we are trying to bring to light here is that though it is vital to ascertain how much nutrition is present in the food initially at the time of harvest, it is equally, if not more, important to track the time lag from farm to fork, or how fast you get your food post-harvest.
By that metric alone, Hydroponics is a clear winner (unless, of course, you grow your food) as most of the hydroponic farms are setup inside or nearby large cities and provide their produce fresh to the consumer. For example, from harvesting to delivering the greens from Green Block Farm’s indoor farm in Maharashtra, we often manage a turnaround time of fewer than eight hours. It cannot get fresher than that.
Additional substances present in the food: We strongly believe that the third aspect that we are going to cover now is the most significant advantage offered by Hydroponics. It is common knowledge that most of the harmful pests affecting plants are soil-based or soil born. Since Hydroponics eliminates soil, it also removes all soil-borne parasites without using a single drop of pesticide. Also, since the water used for hydroponic cultivation is pre-treated and RO purified, even water quality is pristine. The only thing a Hydroponic grower may still need to deal with is air-borne pests (and in an entirely indoor vertical farm like ours, even air-borne pests are a zero nuisance to us). Thus enabling us to grown pesticide free fresh produce. This advantage exists due to the inherent nature of the technology and its way of application for growing.
The bottom line is it depends on the nutrient solution the vegetables are grown in, but hydroponically grown vegetables can be just as nutritious as those grown in soil.
“Much as I think that soil is just great for growing plants, hydroponics has come a long way,” said Marion Nestle, a professor of nutrition, food studies and public health at New York University. “I’ve seen hydroponic producers who have tested their leafy greens for key nutrients, and the amounts fall well within normal limits for their crop and are sometimes even higher.”
Traditionally, plants obtain nutrients from soil. With hydroponics, the plants get nutrients from a nutrient dense solution instead.
Plants make their own vitamins, so vitamin levels tend to be similar whether a vegetable is grown hydroponically or in appropriate soil conditions. It’s the mineral content that can vary in hydroponic crops, depending on the nutrient used.
“You can enhance” a plant’s nutrient levels “simply by adding nutrients to the solution” they’re grown in, said Allen V. Barker, a professor at the Stockbridge School of Agriculture at the University of Massachusetts, Amherst. “You could add whatever you wanted: calcium or magnesium, or minor elements like zinc or iron.” The result is that vegetables grown hydroponically could even be “nutritionally superior” to traditionally grown ones, he said.
Keep in mind that nutrient content varies for produce in general, regardless of the growing method. The differences relate to the type of fruit or vegetable, the condition it is grown in, the time of year it is harvested, how long after harvesting the crop gets eaten, and how it is handled, delivered and stored from farm to fork.
Remember, too, that these differences in nutrient levels are unlikely to have a significant impact on overall health. The key message from most nutrition experts is simply the more vegetables you eat, the better for mankind.