All plants depend on good soil for their prosperity. But all potting mixes are not created equal. The term “potting soil” is generic in the marketplace. Unless a package indicates the ingredients, it is difficult to know what you are buying. Potting soil varies considerably, but it is often little more than sterilized topsoil, which by itself is much too heavy for potted plants. Container plants need porous soil that holds some moisture but also drains well and is rich in nutrients.

For most container gardens, choose a potting mix. Ready-made packaged mixes usually contain organic matter (peat moss, coir [coconut husk], or decomposed bark) and some form of aggregate (perlite, vermiculite, or sand) in various proportions. These ingredients allow water to properly drain, enabling air to penetrate the soil.

Read the package label to determine if the mix is adequate for your plants’ needs or if you will need to add ingredients to make an ideal mix. Experiment with potting mixes to see which ones work best for your plants.

Fertilizers and More

High-performance plants need nutrients to produce vigorous foliage and bright blooms. Regular fertilizing during the growing season is important to keep potted plants healthy, because frequent watering flushes important nutrients out of the soil. More frequent fertilizing is needed by some plants, including vigorous growers, flowering plants, and those growing in soilless mix. Less frequent feeding is required by other plants, such as many foliage-type houseplants, citrus, cacti, succulents, and plants that rest or go dormant over winter.

The numbers

Although fertilizer can be called plant food, plants make their own food via photosynthesis. Fertilizer amends the soil with the nutrients plants need most. The three key nutrients are nitrogen, phosphorus, and potassium. Nitrogen is needed for stem growth and green leaves; phosphorus fuels strong roots and flowering; potassium enhances

• Slow-release fertilizers are coated so they break down slowly and release nutrients gradually.
• Water-absorbing polymer crystals help minimize watering because they store excess moisture and release it over time. Buy potting mix with crystals already included or add them yourself.
• Water-soluble fertilizer is mixed with water and applied frequently throughout the growing season.
• Granular fertilizer works best when blended into potting mix before planting. Use it according to the product manufacturer’s directions.

Drainage

A potted plant’s survival depends on a drainage hole or other means of releasing excess water. Without adequate drainage, the plants’ roots can suffocate and rot. If a container doesn’t come with at least one drainage hole, drill one.

In lieu of drilling into a container, use it as a decorative cachepot instead, hiding the nursery pot inside it. When watering a plant in a cachepot, pour off any excess water that drains from the nursery pot and is not absorbed into the potting mix.

Material matters

Key to a plant’s success is the container’s ability to hold soil and moisture, which depends on its construction material. Porous materials, such as terra cotta and wood, dry out faster and are good for plants that prefer soil on the dry side. Nonporous materials, including plastic, metal, and glazed ceramic, hold moisture longer and more evenly. Well-made containers stand up to watering and weather. Unless treated with a waterproof sealant, wet wood rots and metal corrodes.

Types of Containers

Available in an enormous range of styles and materials, containers accent the color and style of a home, whether they’re new or old, and even whether they hold plants or not. Each type has benefits and drawbacks for you to consider.

The Right Light

Light is vital to plants. Their ability to grow, maintain health, and produce flowers depends on light. If a plant is in more or less light than it needs for optimum growth, it will be stressed and more prone to problems, such as weak growth, minimal flowering, disease, and pests. Too much light may cause whitish scorched marks on foliage, wilted and shriveled leaves, or bleached leaves. Symptoms of insufficient light include stretching or leaning toward a light source; sparse or spindly growth; loss of foliage color or variegation; and smaller, thinner, easily damaged leaves.

Before you bring a plant indoors, identify the amount of light it will need and the location where that light is available. Experiment until you discover where the light in your home best suits a plant.

A plant tag usually tells you what level of light a plant needs: low, medium, or bright. Ideal light levels vary by plant species and sometimes by cultivar. Low light may be enough to keep a plant alive but not enough to promote flowering. Bright, direct light in a south- or west-facing window suits succulents and seedlings, but it could toast African violets and bromeliads. Look for shadows—the brighter the light, the stronger the shadows.

How to Water

As with the other elements, a plant’s need for water is individual, and there are many variables. A plant’s needs change with the seasons, as plants absorb more water when the light is bright, temperature is high, and humidity is low. The thirstiest plants include those with flowers, large leaves, tropical or marshy origins, or large root balls in a confined space. A lightweight soilless potting mix dries out faster than heavy potting soil, and small pots dry out faster than large ones. Fast-growing plants (ferns, dracenas, palms) need more water than slower-growing ones (holiday cactus, Sansevieria).

Check the soil of indoor potted plants weekly by feeling the soil before watering or using a moisture meter. Using your finger as a dipstick, poke it into soil up to the first knuckle to determine if the soil has begun to dry; up to the second knuckle to feel for moisture. You will learn to feel the difference in soil that is dry, damp, moist, and wet, and when water should be added to maintain a level of moisture or dryness.

Overwatering is the single-most common cause of indoor plant death. Underwatering and overwatering can have the same symptoms: wilting, pale, lackluster, and dropping foliage. Without enough water, a plant becomes stunted; leaves turn yellow or brown. With too much water, roots can’t function normally and the plant suffocates.

Each plant also has preferences for moisture and heat, depending on its origin from a tropical,

TIẾNG VIỆT

GET THE DIRT ON WHAT IT TAKES TO CULTIVATE HEALTHY PLANTS INDOORS. START WITH A FEW POTTING SOIL POINTERS AND FERTILIZER FACTS, THEN CHOOSE THE BEST CONTAINERS FOR YOUR PLANTS AND GIVE THEM THE RIGHT LIGHT AND WATER.

WRITER: KATE CARTER FREDERICK
PHOTOGRAPHERS: MARTY BALDWIN, BLAINE MOATS, AND DEAN SCHOEPPNER