The Root of the Matter

 

sprout roots cross section

It’s easy to spot possible problems with a plant’s leaves, stems or flowers. Those are the parts we enjoy seeing every day in our garden. But what about the parts that lie beneath the surface of your garden or container?

We can forget all about the roots when enjoying a plant’s shape and color. But some of the toughest tricks to gardening involve root care – watering enough but not too much; soil drainage to allow roots to gather water but not sit in them; ability for roots to take up oxygen, and ability of roots to grow outward to support the plant you see above ground. How do you know your plant’s roots are healthy and why is it important?

Roots Affect Plant Health

The way roots grow, and their health, have a profound effect on the size a plant reaches, its vigor, and how it responds to watering or other care you give the plant. The main function of these leafless, underground stems is to absorb moisture and nutrients from the soil around them. The roots store the plant’s food to keep it nourished and alive. Roots also help stabilize a plant in the soil or potting mix and physically support the plant’s main stem or trunk.

carrot fruit and stems with dirt on the roots
A carrot is a taproot.

Types of Roots

There are various types of roots, although most root systems branch out under the soil. You might have heard of a taproot, which is a primary root that grows straight down into the soil and develops few to no root branches. Picture a carrot. The part we eat actually is a taproot. That’s the good kind, but a taproot can be a problem for gardeners. Some trees, such as pecans, grow deep taproots. This makes them much more difficult to dig up and transplant.

Some roots have lateral, or secondary, roots that branch off from an existing root. This happens with fibrous roots because their primary root eventually stops lengthening. Fibrous roots are lighter and smaller in diameter because they have less cell activity than standard roots.

One of the biggest problems with roots is restriction of their growth. This is easy to see when you lift a new plant out of its nursery pot. Some have roots circling in the shape of the container; the roots received good nutrition from the potting mix and plenty of water from garden center staff, but had nowhere to go. When planting, always dig a hole larger than the root ball – up to three times as large for trees and shrubs. And loosen the soil around the outer edges of the hole. If the ground is compacted and dense, roots will have to work harder to spread.

wilting zucchini plant from disturbed roots
This zucchini looks bad. Because I ripped its roots when I moved the pot.

A second problem is underwatering (especially a tree) or watering in brief, shallow periods instead of long, deep soaks. Short watering doesn’t penetrate very deeply, so the roots grow close to the surface. And that can bring on other problems, including damage from lawnmowers or foot traffic. But with less frequent and deeper watering, roots grow downward as they seek moisture.

Roots as Plant and People Food

For plants, the structure and quantity of roots help determine how much water and nutrition the plant takes in. That’s why it is so important to water a plant more in its first season or year of growth than it will need later. The extra water helps those roots take hold and grow so they can store food for the plant.

Beet roots and leaves are edible.

 

Aside from carrots, potatoes, sweet potatoes, radishes and beets are among common roots people eat. The mature root – a tuberous root in the case of a potato or sweet potato – holds lots of nutrition.

One final tip – buying a plant that has roots wrapped around inside the pot (rootbound) can make for more challenges when you plant it. You should tease or slice the roots near the outer bottom to help stimulate new growth. But if a plant’s roots are brown or dry, move on to another plant.

 

 

 

 

 

 

 

10 More Gardening Terms Explained

Last fall, I listed and defined 10 gardening terms that you’ll see often in books and blogs about gardening. I’ve got 10 more to cover just before gardeners start buying new seeds and plants and planning their 2018 gardens.

gardening basics
Gardening can be easy, and knowing what terms experts use can help you have success.

10. Zone

A zone is the climate-related gardening region in which you live. The most common designation that likely appears on your plant tags or care information is the USDA hardiness zone. It’s based mainly on how cold your lowest lows fall in winter. A zone in the Southwest can match one on the East coast, but other conditions such as temperature extremes in the day, soil makeup, wind or humidity also can affect how well a plant grows. New Mexico has 10 variations of the USDA zones, from the mountains’ 4b (slightly warmer than 4a) to 9a along the southern Rio Grande valley. Learn more about USDA and Sunset zones here.

mountains of new mexico
In the Sacramento Mountains outside Ruidoso, N.M, we saw some plants we can grow in the valley below, but the zones change rapidly.

9. Root-bound

Plants for sale or that you’ve placed in a container can become root-bound. This means the roots couldn’t spread outward as the plant grew, so they began circling the container borders and might be poking out of drainage holes on the bottom. Most plants grow poorly and can even die when this happens, but see this article about house plants that like crowded root conditions. If a root-bound plant for sale looks otherwise healthy, you can take a chance on it. Break up the roots with your fingers and spread the roots out when you plant in the ground or in a larger container. Be sure to check for signs of circling roots on indoor and outdoor container plants.

adenuim in pot
This gorgeous adenium can handle being root bound and does best when not planted too deeply.

8. Heirloom

When we sell tomatoes at market, we get plenty of requests for heirloom varieties. These grow from older, more pure seed lines handed down for generations. They’re often some of the tastiest and most nutritious vegetables you can find. Ambitious gardeners prefer heirlooms so they can save their own seeds for planting the next year. However, they might not resist disease as well as a tomato variety bred to do so, and heirloom varieties like Brandywine don’t do well in shorter growing seasons like ours. Still, every gardener should try an heirloom flower or vegetable at some point to enjoy the benefits of the carefully selected qualities bred into the plants.

Blue Lake green bean heirloom
We’ve continued to plant Blue Lake heirloom beans every year. The plants do well and the beans are crisp and delicious.

7. Hybrid

When breeders create hybrids of any plant, they control the results by selecting favored qualities of both plants and cross-pollinate them to produce a new plant with the best of each. The careful controlling of the process by breeders can take years of care. Hybrids give us vegetables resistant to diseases, with richer colors or flavors or that produce in shorter growing seasons. Hybrids are not the same as GMOs; genetically modified plants are developed by altering DNA in a lab.

6. Crown

This is the part of any plant where the roots and stem join. See this demonstration for placing the crown at the right depth from Fox Hill Gardens. This is important because the crown should be just about soil level when planting most plants. Be sure to check instructions that come with individual plants, especially roses and trees, about depth of planting and whether to mulch to help protect the crown.

5. Seed start

A seed start is the small plant, or seedling, you grow from a seed. New gardeners can be confused about whether they can plant a seed directly in the ground (direct sow, below) or whether the plant will do better started indoors under grow lights and then transplanted into the garden at the appropriate time. You can save money starting seeds, and basil and zinnias are two easy annual plants to start from seed. Others, such as cucumbers, don’t transplant well. This article from Gardener’s Supply Company has great advice on starting seeds, which can help save money on new plants each spring.

seed starts
Last spring’s seed starts under grow lights. We started herbs, vegetables, and perennial and annual flowers.
snapdragons
Check out these snapdragons grown from that flat of flower starts. And they lasted into fall, at least until deer ate them.

4. Direct sow

This means to place seeds directly into the ground in the garden or in a container. Carrots, lettuce and green beans are easy vegetables to grow from direct sowing. Just follow the directions on the packet about seeding time, planting depth and spacing. You might have to thin your seedlings later. One positive: if you plant too soon or too deeply, seeds cost so little you can often try again!

3. Determinate

The tomato terms determinate and indeterminate have caused me plenty of confusion in years past. I don’t know why I have such a hard time remembering them. Determinate varieties grow to a set mature size and produce most of the fruit within a few weeks. Then it’s done. Determinates also are called bush varieties.

indeterminate tomato in container
Often, determinate, or bushy, tomatoes do best in containers. But we also grow indeterminates, which need cages for support.

2. Indeterminate

These tomatoes continue growing until hit by frost, and sometimes are called vining tomatoes. They produce fruit steadily through the growing season, depending on weather conditions, etc. They can grow out of control if not staked. I’m planning to remember the difference by noting that indeterminate implies the plant does what it wants. But I wish someone would invent a better set of words!

plant growth habit
Varying growth habit adds interest to a xeric garden.

1. Habit

Basically, a plant’s habit refers to the direction it grows, such as upright, mounded or prostrate (spreading low along the ground). It also refers to terms such as shrub vs tree. A shrub, for example, grows to only about 15 feet high and has multiple stems in the ground, whereas a tree usually has a single trunk and greater height. This handout from the University of Colorado shows growth habit shapes and definitions.