Fruits and Vegetables

I’m going to tell you how a butternut squash can be a fruit and a vegetable at the same time.

Many, many plants reproduce by creating seeds, which is an embryo (or germ) locked inside a nutrient package surrounded by a casing.  Ferns and mosses are the most familiar plants that do not create seeds.  These plants reproduce in a more primitive fashion, in a manner using dispersal of spores.  The vast majority of plants on earth, both terrestrial and aquatic (algae are not technically plants but pre-plants), reproduce by seed.  And the vast majority of seed-making plants are of the flowering clade, the Angiosperms.

All, and I do mean all, of the crops we grow on our farm are angiosperms.  Every crop we grow reproduces by first making a flower, then making fruit which contains seeds.  A familiar example is the tomato, which blooms yellow flowers in clusters.  Soon the yellow blossoms drop away and the incipient tomato (the fruit of the plant) begins to fill and eventually ripen.  During the green phase of the tomato nutrients are being shunted to this part of the plant to make viable fruit (fruit that will grow to maturity without rotting or being aborted) and viable seed.  Once the tomato fruit is ripe its seeds are viable and you can take the seed from your favorite tomato and, often, grow the same type of plant from the seed.

Now we all know that tomatoes are considered vegetables colloquially.  They are not referred to as fruit because, again colloquially speaking, they are not super duper sweet (like apples, mangoes, raspberries, and blueberries).  But tomatoes are technically fruits and just as entitled to the term as any sweet fruit is.  The same is true of cucumbers, zucchini, corn, wheat, peppers, eggplant, okra, rat-tailed radish, and butternut squash.  All of these vegetables have to be grown and tended with flowering and then fruit-development in mind.  Like I mentioned earlier all of the crops we grow are angiosperms.  This means they are all flowering plants and, there for, fruiting plants.  Let me explain:

Many crops are harvested prior to flowering (such as leafy greens, lettuce, carrots, beets, etc) and others are harvested during flower development (such as broccoli, cauliflower, celtuce, etc).  These plants are not permitted to “go to flower” because their culinary appeal is not related to their fruit-production.  For instance you have probably never eaten lettuce fruit, carrot fruit, or turnip fruit.  Growers who are interested in saving seed from these types of crop do allow them to “go to seed”, and the seed is always found inside a fruit.  This means that vegetable fruits will have seeds inside (like peppers or butternuts) while vegetable non-fruits will not (like broccoli or a carrot).

Fruits come in a enormous diversity of shapes, sizes, densities, and with varying water content.  It is easy for us to relate a tomato to an apple because they both are relatively similar in shape and both have a high water content and both can be bitten into without any processing.  Acorns on the other hand are a different matter.  Acorns are fruit.  They have a seed inside of them but they are more than just seed tissue.  Let me explain:

When flowers develop they often have both male and female organs present in one blossom.  The female organ is typically in the center of the blossom and looks sort of like a vase, with a fat bottom, a skinny stem, and a fat lip at the top.  The fat bottom portion is what we need to look at.  This is the ovary of the flower and, like a human ovary, it contains unfertilized eggs (or ovules).  Each ovule, when fertilized, becomes an individual seed.  Some ovaries have many ovules (like a tomato) and some ovaries have only one ovule(like an oak tree).  The ovary is important because that is what will become the fruit of the plant.

Once a flower is pollinated and the ovules start to develop into true seeds the ovary starts to change.  In a tomato you can watch the ovary grow slowly into a green tomato.  Once the tomato is ripe you can open it up and see all the viable seeds inside.  Each one of those seeds was a microscopic ovule inside the tiny ovary of the tiny tomato flower.  Tomato seed is found inside the tomato fruit.  Oak tree fruit are different in shape, size, water-content, and have a different number of seed inside their fruit.  But they still start out as individual flowers and then turn into fruit (“acorns”) which house the seed inside.

The term for the flowering/fruiting plants, “angiosperm”, means “seed in a vessel.”  “Seed inside a fruit.”  All of the great diversity of flowering plants, from sedges, grasses, and duckweed to magnolias, spinach, and cacti make fruits to house their seed.  Plants like pine trees and spruce trees do not make flowers (and there for do not make fruits) when they make seed.  They are in the gymnosperm group, or the “naked seed” group.

Now to wrap up.  Butternut squash plants make two types of blossoms, male flowers and female flowers.  These different blossoms will be found on the same plant.  When the female flowers are pollinated by a squash bee the large blossoms drop away and the fruit begins to fill.  This is also the time that the seed, or the fertilized ovules inside the fruit, are maturing.  A tremendous amount of nutrition has to be supplied to a developing butternut fruit as they are large and have lots of (also large) seed. Unlike summer squash, where fruit is harvested before seeds are viable, winter squash (like butternut) is harvested after the plant has died back and the fruit has fully matured.  This is why you can save seed from winter squashes after harvest and typically not from summer squashes.  Although butternut squash is very sweet it is still considered to belong in the humble “vegetable” category.  But we know that, really, they’re fruits.


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