Home gardening or purchasing from a local organic/farmers market can add variety to your pantry, flavor to your meal and color and aesthetics to your plate, all while reducing your food mile. But is this produce more nutritious? Right now many of you already have an answer to this question based on your current knowledge! Whether your knowledge comes from grandparents, parents, the farmer next door, cultural practices, hard science, practice-makes-perfect, a book from the library or something you read on ... well someone's blog! You already have an answer based on your current knowledge 😳. So here is a little more knowledge from a retired state university extension agent who grows "pesticide free" produce in a high tunnel.
Let's approach "better" from the standpoint of nutrient rich and pesticide free produce. Pesticide free in home grown is easy so lets cut-to-the-chase and focus on nutrients. A lot of produce grown commercially is not as nutrient dense as it once was. In fact, looking at the change over time, Scientific American reported on a study of "reliable declines" in nutrients published in 2004 in the Journal of the American College of Nutrition. These nutrients were identified by USDA between 1950 and 1999 for 43 different vegetables and fruits and included drops in protein, calcium, phosphorus, iron, riboflavin, B2 and C. While this is not a fresh article, it shows how nutrient declines have occurred in commercial agriculture. Much improvement in produce has focused on "...greater yield, pest resistance and climate adaptability" and "have allowed crops to grow bigger and more rapidly ... but their ability to manufacture or uptake nutrients has not kept pace with their rapid growth" as stated in the article by Donald Davis. How can we correct this lack of nutrients in the home garden?
Gardening is a little science meets art, sprinkled with a touch of love and a whole lot of patience with the weather, insects and weeds. To keep this simple, think of produce nutrient value as something like this ...
plant variety + soil health + growing practices + food preparation = nutrient value
- Plant Variety: The plant variety you choose whether a hybrid, heirloom or other, can affect nutrient value. For instance, each tomato variety has a different nutrient value as do other vegetables. In 2013 Professor Allen Barker and his team studied the nutrient content of a selection of fruits and vegetables to see how they were affected by chemical fertilizers, organic fertilizers or compost. They tested 24 varieties of tomato, 35 types of cabbage and 18 different lettuces and within the same fertilizer groups found differences in nutrient values in each species but was not different between fertilizer types. Compost was a little lower. I for one, prefer the flavor of heirloom varieties (50+ year varieties) and am a naturalist at heart! In my personal taste comparison, heirlooms have a robust flavor I have not found in modern hybrids developed for higher yields, easier handling, better appearance and marketability at the expense of nutritional content.
- Soil Health: All I can say is ... get your soil tested! Amend your soil based on nutrient need rather than blindly fertilizing. Depleted soil nutrients mean depleted produce nutrients! Soils should be amended based on a good garden soil test. Manuring the garden every year can end up with toxic amounts of nitrogen, phosphorus and potassium followed by contaminated surface and ground water, excessive weed growth and pest issues. There are some awesome fertilizers on the market with much needed micro nutrients you won't find in manure. Plant compost will also help with some of the micro nutrients. Harvesting produce removes macro+micro nutrients annually and must be replaced whether you are growing conventional or organically. Test in the spring to see what you need to add and test in the fall to see what you removed. after a couple years you will get an idea of your fertilizer needs. It's not rocket science. Every state has an extension office that can help you with a fertilizer plan based on your needs and soil texture. We added an organic composted poultry/cedar wood chip fertilizer this year with great results, plus the organic matter of this fertilizer helped with water holding and nutrient retention. In addition we irrigate using t-tape you can see in the photo above. We add liquid fertilizer through a venturi system that runs the fertilizer in through the t-tape. We fertilizer when the plants tell us to fertilize. By reading your plants you can tell what nutrient they need. (Nutrient Management Modules) Oh and don't get me started on the value of soil microbial life! That will be another blog ... stay tuned!
- Growing Practices: Growing practices may affect nutritional value of harvested produce. Some nutrient movement can be affected by water. For instance when a tomato is watered inconsistently you may see blossom end rot which could be lack of calcium to build cell walls or a pseudo deficiency when calcium is present but doesn't make it to the blossom end of the tomato when watered inconsistently. (That was a run on sentence but I'm leaving as is!) Timing of harvest can affect nutrients in produce, such as changes that occur when produce is over ripe. Lastly, you definitely have control over how many pesticides you use in your home garden. We do not use any pesticides in our home garden. Yes, we have lost produce to aphids, deer, birds and rodents. However, there is no value to us in eating produce that has been treated with pesticides ... so I guess we share our produce with a variety of other critters.
- Food Preparation: Food preparation and food preservation removes nutrients from food and each practices adds to the nutrient loss. The greatest nutrient retention for food storage is drying food to keep it shelf stable and hold the most nutrients. Blanching for freezing, cooking, hot water bath and pressure canning remove over half of the nutrients in our food! Sheesh that too will be another blog ... so again, stay tuned!
So, is home grown produce better for you? I guess it depends on you and how you raise your produce! LACK OF soil health is the #1 cause of nutrient poor produce and soil health is the #1 way to improve the nutrient density of produce.
