Having a green thumb or not, keeping a garden alive is hard work. They need a lot more than water and sunlight, and perhaps not everyone who tries their hand at gardening is aware of that.
Plant diseases can wipe out a garden, causing frustration. The most mystifying questions facing pros and newbies alike are, "How did my plants get sick?" and, "Will they die?" First, one has to understand where plant diseases stem from, and it's likely due to the "disease triangle." Diseases typically take hold when three things are present. It begins with a plant that can get sick (a host), but it also requires a pathogen (like a fungus, bacterium, or virus) that attacks the plant, and environmental conditions (humidity or drought) that can impact it.
If starting a garden is a task on the "to-do list" for the family, one must do more than just water and remove weeds. In this list we've gathered up 15 ways to eliminate at least one side of the disease triangle (whether it's an indoor garden or outdoors) and keep plants alive, thriving, and healthy all year.
Examine Plants Carefully Before Buying
The easiest way to limit disease is to avoid introducing it in the first place. Make sure the plant is healthy before planting it by inspecting the leaves for any signs of spots, mold, or dead parts.
Check the plant's roots before buying or planting by placing a hand on the soil's surface with the plant stem between the fingers. Gently invert the pot and lightly tap the edge of the pot against a solid surface to loosen the roots from the pot. Roots should be firm, usually white (as in the photo above) and spaced all over the root ball. Dark or mushy roots are not a good sign.
Choose Pots Carefully
Planting an indoor garden means making the perfect home for plants. Most houseplants are sold in standard plastic pots and need to be repotted. The purpose of a container is to hold the right amount of soil for the plant to live and grow. In other words, the container should match the size of the plant and continue to do so as it grows. The best pots have holes in their bottoms for excess water to drain out.
Remember, if water collects in the bottom of a pot, it can cause root rot, which eventually kills plants.
Plant Disease-Resistant Varieties
These plants have developed a complex defense system against diverse pests and pathogens. Disease-resistant plants are those that might get sick with a particular problem but will fight off the disease instead of dying due to the cause of it. Choosing these varieties gives a better chance for success.
Just ask nursery employees and fellow gardeners who can help identify the best or most resistant varieties of plants. Reference books may also list plants and varieties resistant to particular diseases.
Choose & 'Site' Plants Appropriately
Most, if not all, plants come with instructions. Successful gardening is based on choosing plants that are appropriate for a specific USDA zone and site. A small tag usually lists the kind of environment it grows best in. For example, a shade-loving plant, like impatiens, will grow poorly in full sun or dry out, which will stress it.
Plants have defenses similar to the human immune system, which swing into action when plants are under attack. If plants are under stress because they're in the wrong environment, they cannot react with full strength to fight off or recover from diseases.
Give the Plants Space
Plants that are placed too closely to each other tend to grow poorly due to competition for light, water, and nutrients. Crowded plants create their own humidity, which allows diseases like powdery mildew, rust, and downy mildew to thrive and create a weak immune system.
To avoid this, give the plants space to breathe.
Prune Thoughtfully
What is pruning? Pruning is controlling a plant's growth and development into specific growth patterns. It usually stimulates growth, but how severe the pruning is will determine future growth.
Severe pruning (or cutting way back) will result in vigorous growth for a plant, while light pruning will allow slower growth. Not all plants will need pruning, so make sure to research before getting out the clippers.
Water Properly
Of course, plants need water. But too much or too little can kill them. Overwatering can lead to root rot and other diseases. To avoid giving diseases an environment they love, choose watering methods that limit moisture on a plant’s foliage. Soaker hoses and drip irrigation accomplish this. If watering by hand, hold the leaves out of the way so the water goes into the soil.
Repot When Necessary
When is it time to repot a plant? Signs include, the plant looks too big for its pot; the roots are growing out of the drainage holes; water is sitting on top of the soil and not absorbing; and/or it's been years since the plant has been repotted.
When repotting make sure to have the proper tools. Look for a larger pot with drainage holes, use a coffee filter to cover the holes to prevent the soil from falling out of the holes, water it before removing into the new pot, and prune old roots and untangle them to help it grow in its new home.
Use Clean Tools
Tools should be checked and cleaned after each use to prevent spreading diseases. Use a disinfectant, like bleach, to make sure tools are sanitized. Keep tools in good condition by oiling them regularly to keep moving parts working smoothly so they don’t catch or rub.
Use Fully Composted Yard Waste
This popular gardening technique goes beyond just collecting organic trash. In a compost pile, materials decompose at different rates. Thorough composting generates high temperatures for extended lengths of time, which kills diseases in the material.
Infected plant debris that has not undergone this process could reintroduce diseases into the garden. If not sure of the conditions of the compost pile, avoid using compost around sensitive plants.
Add Mulch Around Plants
Adding mulch will lock in the moisture and keep out the weeds. Using the clippings from the garden as mulch is like killing two birds with one stone. Other alternatives include crushed rock, newspaper, old leaves, or wood chips and shavings.
There is a wide variety of mulches, which can be broken down into two groups: organic and inorganic. Organic mulches break down over time and contribute to soil health. This can be helpful for poor soils. Inorganic mulches protect from erosion and mechanical injury from trimmers and lawnmowers.
Keep an Eye on Bugs
Garden pests can make plants look unattractive, and they can also introduce diseases to the plants. Not all insects are harmful, including ladybugs, ground beetles, and praying mantises, but pests that threaten plant health include slugs, snails, aphids, and caterpillars.
Keep Plants Cool
If this isn't obvious, plants tolerate heat differently. Some plants, like cactuses, can handle high heat, while others will wilt and die when the temperatures soar. Plants also have different sunlight needs — some will become spindly without adequate sun, while others will show scorch marks in intense sunlight. Choose plants that suit the climate and place them according to their needs for sun or shade.
Check Humidity Levels
For indoor plants, humidity plays a big role. In centrally heated rooms, the air can be extremely dry, with humidity levels as low as 15%. Only dry-air plants such as cacti and succulents, will thrive in these conditions.
To prevent leaves from drying out, most houseplants prefer humidity of 40 to 60%, which is likely in a bathroom or steamy kitchen. Misting, double potting, and humidifiers will raise the air moisture level. Just monitor frequently.
Clean Up in Fall
Diseases can overwinter on dead leaves and debris and attack the new leaves as they emerge in spring. Make sure to remove leaves, stems, and debris before winter sets in. It is always best to clean up the garden in fall, even in a moderate climate.
