Most of us garden because fresh fruits, vegetables, and herbs taste better.
But why do they taste better? In fact, why do plants have flavors at all?
It ends up that flavor is all about transmitters and receivers, but not the type that deliver your favorite songs or movies.
Plants have flavors because of the chemicals they use to communicate and to protect themselves. They use these chemicals to attract pollinators, inhibit bacterial and fungal pathogens, and, in some cases, slow the growth of competitors (allelopathy). Plants protect themselves by creating chemicals that make them unpalatable to attacking insects, herbivores, or pathogens.
Plants use one chemical, ethylene gas, to trigger neighboring plants to ripen. In nature, this means there will be a bunch of ripe fruit available at the same time, increasing the odds of birds and animals coming to eat and dispersing seeds. This ripening cascade works the same way leaves change color in autumn. A few trees start doing it, which triggers neighboring trees to follow suit.
But how do those chemical communications translate into flavors?
A matter of taste
When we eat something, our taste buds collect information about the chemicals in our food that dissolve (soluble). At the same time, our noses collect information about the chemicals released into the air as we chew (volatile). It ends up that these are the same chemicals plants use.
Taste and smell are inseparable. In fact, your sense of smell is estimated to be 80% of the flavor experience. Don't believe me? Try closing your eyes, plugging your nose, and taking a bite of onion - you'll swear it's an apple.
Taste is a matter of acids and sugars. There are different types of sugars. Most fruits contain varying combinations of fructose, sucrose, glucose, and sorbitol. Fructose has the most sweetness and sorbitol has the least.
Our taste buds sort sugars and acids into five categories: sweet, sour, salty, bitter, and umami. Umami is a protein flavor. Some cultures also include fattiness (oleogustus) and pungency.
Did you know that children have 10,000 taste buds and older adults only have 5,000? And dogs have less than 2,000 (which may explain why they are willing to eat some really gross things). They simply don't taste them. On the other hand, our canine companions have over 300 million smell receptors, while we have 50 million or so.
Scents and smells
We sort out aromas over those 50 million receptors using more than 650 different types of olfactory nerve endings found in our noses.
I once gave my students the assignment to create their own word. One 6-year-old student came up with 'olfactorized'. When I asked her for a definition, she said it meant being attacked by a bad smell. I miss teaching.
But how can a plant smell something without a nose? It ends up that plants have sensory receptors, much like our taste buds, that allow them to identify volatile chemicals (essential oils) floating around in the air. Dodder, for example, is a parasitic plant that uses its sense of smell to find host plants, sniffing out its favorites and avoiding sick plants.
Some of those scent chemicals include:
Clearly, there are many factors that determine a plant's flavor and some of those factors are under your control.
Genetics play a big role in flavor. If you want to taste lime, you wouldn't plant a grapefruit, right? When selecting plants for your garden or landscape, start by choosing varieties that are suited to your microclimate and that produce the flavors you want.
Environmental conditions also impact flavor. If your fruit trees and tomato plants don't get enough sunlight, they cannot produce the sugars that make them taste good. Proper tree training and plant spacing, pruning, and reflective mulches can be used to increase the amount of sunlight that reaches inner branches.
If your plants are allowed to produce too much fruit, the flavor won't be as good, either. Fruit thinning allows plants to focus their energies on quality, rather than quantity. In the same way, too much irrigation can be just as bad as not enough. During the growth phase, plants need plenty of water. As crops get closer to harvest time, you can increase flavor by reducing the amount of water available. This is called deficit irrigation.
The same is true for nutrition. If your plants get too much nitrogen, they will have more of a green, grassy flavor. Less nitrogen translates into more fruit flavor.
When you harvest your fruits also determines flavor. Most store-bought produce is harvested before it is fully ripe, to allow for shipping and storage. One of the nicest things about growing your own is that you can wait until that perfect moment before taking a bite.
What are your favorite garden flavors?
You can grow a surprising amount of food in your own yard. Ask me how!
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