Fall Gardening Know How, Part II: Root Crops

Posted: August 5, 2016

Earthy. Sweet. Pungent. Sifting through gardening blogs and seed catalogs, these are some of the many adjectives used to wax poetic about the flavors of root vegetables. If asked about their importance to modern cuisine, a chef would likely add versatile and nutritious to their description. Root vegetables like beets and rutabagas can be steamed or roasted slowly until their sugars caramelize. Carrots and radishes, also delicious cooked, are most often enjoyed raw. No matter how you like your root vegetables prepared, they are nutritional powerhouses packed with fiber, vitamins, and the plethora of minerals they accumulate from the soil.

Cultivating cool season root crops for a fall harvest, starts in late summer-early fall. The root crops we plant now are cool season vegetables that can be started when temperatures are still warm (seeds germinate at 45-85˚F), but need to mature as temperatures cool in the fall. High temperatures (70˚F and above) during maturation can make roots inedible and cause plants to bolt and die. Cold temperatures also aid the process of converting starches into sugar, sweetening their flavor.

Root vegetables thrive in loose, fertile soil that is well-drained and free of rocks. Given the main goal is to harvest large, healthy roots it makes sense that ample attention should be paid to your soil. Prior to planting, loosen the soil to a depth of 12″and add aged compost. Avoid adding too much nitrogen which can cause excessive top growth at the expense of roots or even cause roots to branch, as in the case of carrots. Provide consistent moisture throughout the growing season to further ensure a bountiful harvest.

In the proper environment, your root crop harvest will store for months without perishing. For long term storage, pack root vegetables in sawdust or sand, and place in a cool (32˚F), damp place (85-90% humidity). If you do not have a bona fide root cellar, a cool basement or the crisper of your refrigerator works. Many root vegetables, like carrots, can be stored in the ground over winter and harvested as needed. In areas with harsh winters, protect below-ground root vegetables with a 2″ layer of mulch (wood chips, leaves, straw, etc.).

Root Crop Planting Guide

Beets (Beta vulgaris)

Rainbow Blend Beets sliced in half

Variety: Rainbow Blend Beets

What is there not to love about beets? They are one of the sweetest (literally!) and most vibrantly colorful vegetables you can grow. Start your beets around 8 weeks before the first average frost and again every couple of weeks for a continual harvest. Direct sow outdoors ½” deep and ½” apart. Most beet seeds are multigerm, meaning that what looks like a single seed, actually contains multiple embryos. This means that from each beet seed you sow, 3-4 plants will germinate in close proximity to one another. Thin these seedlings so that mature plants are 2-4″ apart. A side dressing of phosphorus, in the form of bone meal or rock phosphate, will also ensure your beets produce large, healthy roots. Harvest beet greens as soon as they are large enough to eat. The roots are best if harvested when 1-4″ in diameter.

*If you cannot decide which you love more—beet greens or roots—grow ‘Lutz Green Leaf” for the best of both.

Carrots (Daucus carota)

Shin Kuroda Carrot is short and stubby and great for clay soil

Variety: Shin Kuroda

Carrots are a root crop that, in many areas, can be succession planted for sustained harvest throughout the year. Direct sow carrots ¼’ deep and ½” apart. Thin seedlings so mature plants are 1-3″ apart. To thin, snip seedlings rather than pulling to prevent damage to remaining plants. Cover maturing carrot crowns as they push up through the soil to prevent greening and bitterness. Harvest carrots while they are young and tender or store in the ground over winter and harvest as needed.

*Try the varieties ‘Red Core Chantennay‘ or ‘Danvers 26‘ for a classic long-rooted carrot that is reliable and great for storage. In heavy clay soils, opt for shorter rooted varieties such as Shin Kuroda‘ and ‘Little Finger‘.

Radishes (Raphanus sativus)

Easter Egg Mix Radish - Open-pollinated seedsFast to mature and great soil busters, radishes are often planted in rows alongside other slower germinating root vegetables such as carrots and parsnips. Radishes are typically divided into spring and winter varieties, based on their size and time to maturity. Spring radishes are smaller and mature in 3-4 weeks, while the larger winter radishes require 6-8 weeks to maturity. The title “spring” radish is a bit of a misnomer for the quick maturing types, because the cool weather of fall is also a great time to grow these. Sow spring radishes every couple of weeks for a continued harvest. The best radishes for long term storage are the winter radish varieties. Plant winter radishes so that they mature around the first frost.

Direct sow radish seeds 1/2″ deep and 1/2-1″ apart in rows 12″ apart. Thin so that mature plants are 2″ apart for spring radishes and 6″ apart for winter radishes. Harvest spring radishes when large enough to eat and winter radishes around the first frost.

Spring radish varieties include the colorful ‘Easter Egg Mix‘ and the lovely white-tipped ‘French Breakfast‘. For trusty, flavorful winter keepers, grow ‘Black Spanish Round‘ and ‘Daikon‘ radishes.

Rutabaga (Brassica rapa)

American Purple Top Rutabaga - Open-pollinated seedsRutabaga is the underappreciated champion of fall gardening. Rutabagas are easy to grow, store well for months, and are sweeter than their more popular cousin the turnip. Plant seeds 1/2″ deep, 1″ apart, in rows 12″ apart. Thin to 3-6″ for mature plants.

Rutabaga leaves can be lightly harvested when large enough to eat. Roots are ready for harvest in approximately 90 days or when 4-5″ in diameter.

Turnips (Brassica rapa)

A must-have for hardy winter stews, turnips also stand alone as a great side dish. Direct sow seeds 1/2″ deep, 1″ apart and 12″ between rows. Thin to 3-6″ for mature plants. Turnip leaves can be lightly harvested when large enough to eat. Roots are ready for harvest in 55-65 days or when 2-3″ in diameter.

If you like eating turnips raw, try the white, mild flavored ‘Shogoin‘ variety.

Grow Some Root Crops!

For our great grandparents, the best adjective to describe root vegetables could have been vital. Before refrigeration, growing and properly storing root crops was critical to getting through a long, cold winter. While our modern day lives no longer depend on our root vegetable harvest, we still have cause to grow and eat these delicious and nutritious vegetables.

Written by Renee Fortner, Sow True Seed’s Agricultural Manager


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3 responses to “Fall Gardening Know How, Part II: Root Crops”

  1. shannon holmes says:

    Can these fall veggies be directly sown now? How late in the season is the cut-off? Thanks!

    • Hi Shannon, yes the root veggies are much happier with being directly sown. The cut off depends where exactly you are and what you are planting. You will want to count backwards from your first frost date for your area and that will help you plan you planting date.

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