Spinach, ‘Big Boston’ lettuce, broccoli, carrots, and peas; they like frost that makes them use freezing point depression that releases ‘spinach sugar’ and other sugars by the crops’ name
By Gregory Jackson
(Image by From Scratch Magazine)
What are cold season crops? They are the first plants you sow in early spring, when days are warm and nights are cool, with risk of frost. Frost actually benefits cold season crops for their ability to adapt a strategy they use to survive and thus increase its nutritional content, through a natural process cold “freezing point depression.”
Freezing point depression is a bio-chemistry term that mixes organic or mineral content to prevent water from freezing when temperatures approach 32 degrees Fahrenheit.
I planted Bloomsdale Long Standing Spinach, Big Boston Lettuce, Carrot Chantenay , and Snow Peas (all from Baker Creek), and Calabrese Broccoli (Seed Savers Exchange). Calabrese Broccoli was brought to the United States in the 1880s by Italian immigrants, Carrot Chantenay was introduced in 1929, and Big Boston Lettuce was planted in the late 1800s; all organic and non-GMO.
Cover your soil to prepare it from previous autumn and protect from winter
The planting of these crops began last fall when I began to bury food waste and leaves into the beds. I first thought about adding my autumn leaves into growing beds in a cover crop class I attended with Bethany Majeski, Cleveland Metroparks naturalist at Garfield Park Nature Center, late last summer.
“Soil is always meant to be covered,” Majeski said. “If you think about it, exposed soil gets depleted.”
None of the leaves broke down, but all the food waste was gone. There are even remnants of old corn husks from last year’s organic Bantam Corn, now just shreds of stalk I added to my beds last year. While it is tempting to remove these “unsightly” organic remnants, leave them in your beds. They are there for soil structure to improve drainage and breathability. Shells add slow-release calcium and some shells (like crab shells) contain chitin, which acts like a natural insect repellent for crops: Chitin causes plants immunity to be stronger and healthier. Insects know when a crop is weak and sickly from certain crop pheromones insects pick up and attack it.
But how do I plant seeds on leaves?
First, gently turn in your winter’s cover of leaves exposing soil. Then, gently carve a channel using your finger (I use all four fingers to create a channel about as deep as the width of a table), and set your seeds into channel. Then cover channel with your soil/leaf mix, press gently for good soil to seed contact. I did not water because my soil had plenty of moisture. In fact, the same night, April showers.
The year before I was growing peas where this year’s broccoli and lettuce will grow. Most organic gardeners and organic farmers use peas as cover crops, and then plow them into their beds. I decided to grow peas, which I ate directly from the pods, to enjoy the taste and benefit the bed with legume natural processes that fed atmospheric nitrogen into the soil for this year. The remains of my pea plant where also turned into the soil after last year’s harvest; now the pea plant is completely broken down.
Freezing point depression a little bit of frost makes cold season crops more nutritious
Jere Gettle of Baker Creek, wrote Heirloom Gardener, and noted that a little bit of frost actually adds more nutrients to cold season crops. Here’s why.
Leafy vegetables and root crops taste better with frost because of freezing point depression, observed Joseph West, a sustainable agriculture, engineering, science, and religion writer for SFGate who wrote about cold season crops tasting better just after frost.
“This improved flavor is a pleasant side effect of a plant’s efforts to protect itself against below-freezing temperatures,” writes West. “Hardy plants (such as cold-season plants) are designed to benefit from a principle known as freezing point depression.”
Salting roads in winter time is also known as freezing point depression, where salt lowers the water’s freezing temperature, but other freezing point depression materials could be used, like coffee grounds, pistachio shells, or grounded corn husks.
But instead of salt you could make your own homemade de-icing mix using coffee grounds, pistachio shells, or grounded corn husks to reduce runoff into waterways. Cold season crops release sugar in their leaves.
The crop releases sugars to decrease temperatures at which water would freeze in a cell. For example, a spinach cell, which if it does not release sugars, water in its cells will crystallize and kill cells (and eventually the plant). They act like maple trees during maple syrup season in late February, where frost by night/early morning yields to warm daytime temperatures causes maple trees to flow sap for survival.
During the growing season plants produce sugars through photosynthesis and store sugars in their roots in the form of starch.
“Starch is a concentrated energy source composed of tightly packed sugar molecules,” writes West, “and many plants accumulate starch in their roots to provide energy during winter or early spring.”
Cold season crops are made to save some of their sugars for freezing point depression and some sugars for starch – stored plant energy in its roots – for temperatures above 20 degrees Fahrenheit. Multiple days of freezing temperatures stimulate more crop-specific sugars into the leaves and the nutrient-density or trace minerals in each type of sugar is yet to be known. For example, what are the benefits of consuming “spinach sugar”, “carrot sugar”, “pea sugar”, “broccoli sugar”, or “lettuce sugar”? Not only with better taste, but also sugar combined with iron (spinach) or sugar combined with Vitamin A (carrots), is similar to the benefit of eating an orange for orange juice to get fiber and sugar, instead of solely orange juice without fiber.
Last year, when I planted peas, they formed a beautiful mat of tendrils and spindly vines (you can eat pea leaves and tendrils, by the way), but after a rain it would seem dangerously close to snapping off its roots while draping over my driveway.
Three Sisters is the Native American agricultural technique of growing three different types of crops that depend on each other for better growing conditions: winter squash, corn, and beans.
You can substitute beans with peas, since both are legumes and both like to climb on things.
I planted the peas in a wider bed (about five feet wide and 25 feet long), planting the peas in front and leaving room in the back of the bed for Peruvian Chullpi corn. The other grain I will attempt to plant for the first time is emmer wheat. Emmer wheat (also okay for gluten intolerant diets), will be sown later next month. I am still learning what to substitute winter squash, which is believe to suppress weeds.
This bed was also prepared the same way as above: burying food waste directly into the soil in later summer to early autumn, to benefit the mixing of food waste with leaves. The peas will add atmospheric nitrogen into the soil to feed the corn and the corn will be used as “staking” that the peas will be able to support themselves on. Like beans that like to climb on things, peas like to tendril and wrap itself on things, too. Corn will be for the snow peas to not only support itself, but to keep the plant off the ground for good air circulation.
Snow peas must be picked before the pods swell, the flatter version of other pea varieties, enjoyed in stir fries, or eaten right from the vine.
I reminded our banker to plant her peas by tax time. She said it will be a fun project with her daughter.