Seed catalogs are now showing up in mailboxes, assuring us that spring is not too far away. At UNH Cooperative Extension's Education Center and Info Line, we are already getting daily calls from gardeners seeking advice on how to have their best gardens yet. Let’s take a look at a few suggestions for success in the coming season.
Resistant varieties should be part of the first line of defense for gardeners looking to combat common pests and diseases without relying on pesticides. Tomatoes are a great example of a crop that has seen some very exciting developments in disease resistance in recent years. Some varieties are resistant to early blight, late blight and other diseases all in one. One of the most useful strategies is to remain diligent about the identification of pests and diseases. Once they have been identified, it becomes possible to utilize resistance and variety selection as a major means of control.
Controlling environmental conditions is a strategy that can be very effective in certain conditions. In plant pathology, we often think about the contributing factors to plant diseases within a complex known as the “disease triangle.” For a disease to thrive, each corner of the triangle must contain one of the following: a host, suitable environmental conditions and a pathogen.
"As organic matter decomposes, a constant stream of nutrients, including nitrogen, is released into the soil matrix and becomes available to plants."
Take away just one of these factors, and the problem cannot persist. Many fungal diseases require prolonged periods of leaf wetness to grow. In the garden, consciously implementing good irrigation practices can help tip the scales in our favor. Avoiding overhead watering, providing plenty of space between plants for airflow and watering early in the day to facilitate rapid leaf drying are recommended practices to reduce disease pressure.
Increasing organic matter provides a multitude of benefits in garden soils. As organic matter decomposes, a constant stream of nutrients, including nitrogen, is released into the soil matrix and becomes available to plants. Your soil test can tell you what percentage of organic matter you soil presently contains. It’s a good practice to track this organic matter over time, since every one percent increase in soil organic matter increases soil water-holding capacity by 25,000 gallons per acre. Organic matter can be added to the garden in the form of compost, manure, leaves, straw, bark mulch and cover crops.
Extending the growing season maximizes what we can grow in a given season. Techniques such as cold frames, floating row covers, hoop houses and high tunnels continue to gain popularity, making it possible to harvest some cold-tolerant vegetables well into late fall and early in the spring.
Encouraging beneficial insects involves working with nature to control insect pests. Many beneficial insects feed on insect pests that would otherwise cause damage to our favorite plants. Planting a diversity of flowering plants that bloom over an extended season from spring through fall will help ensure that beneficial insects have the food and shelter needed to set up camp in your garden.
Conserving water has been a major issue over the last few seasons. Smart irrigation technologies like drip or wicking systems can drastically reduce the amount of water needed to keep plants healthy and growing. Properly mulching garden beds add to this conservation effort while simultaneously reducing plant diseases.