Summer is when plants are growing, flowering, and producing fruit at their fastest pace, making proper nutrition essential for maintaining vigorous growth.
Just as people need a balanced diet, plants rely on a combination of macronutrients and micronutrients to support everything from leafy growth and strong roots to colorful blooms and abundant harvests. Understanding what your plants need and when they need it can help you avoid common problems like poor flowering, yellowing leaves, and reduced yields.
Here's a great article with details and specifics for Colorado gardeners on how to fertilize in summer.
General Information: The Big Three Nutrients
The three primary nutrients listed on every fertilizer bag are nitrogen (N), phosphorus (P), and potassium (K).
Don't Forget Calcium and Magnesium
Secondary nutrients are just as important. Calcium helps build strong cell walls and supports healthy root and fruit development, while magnesium is a key component of chlorophyll, allowing plants to convert sunlight into energy. Inconsistent watering can prevent plants from moving calcium into developing fruit, contributing to disorders like blossom-end rot in tomatoes and peppers.
Micronutrients Matter
Plants also require small amounts of micronutrients such as iron, manganese, zinc, boron, copper, and molybdenum. Although needed in tiny quantities, these nutrients are essential for enzyme activity, photosynthesis, and overall plant vigor. Deficiencies often appear as yellowing leaves, poor growth, or reduced flowering.
Feed According to the Plant
Different plants have different nutritional needs. Leafy vegetables benefit from steady nitrogen throughout the season, while flowering annuals and fruiting vegetables generally perform best with fertilizers that contain moderate nitrogen and higher levels of phosphorus and potassium once flowering begins. Trees, shrubs, and perennials usually require much less fertilizer than annual flowers and vegetables, particularly after they are established.
Avoid Overfeeding During Heat Waves
When temperatures climb above 90°F, many plants shift into survival mode and slow their growth. Fertilizing during periods of extreme heat can stimulate tender new growth that is more susceptible to heat stress. Instead, focus on consistent deep watering, mulching, and maintaining healthy soil until temperatures moderate.
Healthy Soil Is the Best Fertilizer
Healthy soil provides the foundation for healthy plants. Incorporating compost, maintaining organic matter, and encouraging beneficial soil microbes improve nutrient availability naturally. Organic amendments such as compost and well-aged manure release nutrients gradually while improving soil structure and moisture retention.
Let the Plant Be Your Guide
Plants often tell you when something is wrong. Pale green leaves may indicate a nitrogen deficiency, while poor flowering or fruiting can point to nutritional imbalances or environmental stress. Before reaching for fertilizer, consider whether heat, drought, overwatering, or compacted soil may be limiting nutrient uptake.
A thoughtful approach to summer nutrition combines proper fertilization with deep watering, mulch, healthy soil, and regular observation. By providing the right nutrients at the right time, you'll help your garden produce vibrant flowers, flavorful vegetables, and resilient plants that can thrive throughout the growing season.
Here's a great article with details and specifics for Colorado gardeners on how to fertilize in summer.
General Information: The Big Three Nutrients
The three primary nutrients listed on every fertilizer bag are nitrogen (N), phosphorus (P), and potassium (K).
- Nitrogen (N) encourages lush green leaves and vigorous stem growth. It's especially important for lawns, leafy vegetables, and young plants. Too much nitrogen during summer, however, can produce beautiful foliage at the expense of flowers and fruit.
- Phosphorus (P) supports strong root systems, flowering, and fruit development. Plants such as tomatoes, peppers, and flowering annuals benefit from adequate phosphorus as they begin blooming and setting fruit.
- Potassium (K) strengthens overall plant health by improving water regulation, disease resistance, and tolerance to heat and drought. During hot summer weather, potassium helps plants better withstand environmental stress.
Don't Forget Calcium and Magnesium
Secondary nutrients are just as important. Calcium helps build strong cell walls and supports healthy root and fruit development, while magnesium is a key component of chlorophyll, allowing plants to convert sunlight into energy. Inconsistent watering can prevent plants from moving calcium into developing fruit, contributing to disorders like blossom-end rot in tomatoes and peppers.
Micronutrients Matter
Plants also require small amounts of micronutrients such as iron, manganese, zinc, boron, copper, and molybdenum. Although needed in tiny quantities, these nutrients are essential for enzyme activity, photosynthesis, and overall plant vigor. Deficiencies often appear as yellowing leaves, poor growth, or reduced flowering.
Feed According to the Plant
Different plants have different nutritional needs. Leafy vegetables benefit from steady nitrogen throughout the season, while flowering annuals and fruiting vegetables generally perform best with fertilizers that contain moderate nitrogen and higher levels of phosphorus and potassium once flowering begins. Trees, shrubs, and perennials usually require much less fertilizer than annual flowers and vegetables, particularly after they are established.
Avoid Overfeeding During Heat Waves
When temperatures climb above 90°F, many plants shift into survival mode and slow their growth. Fertilizing during periods of extreme heat can stimulate tender new growth that is more susceptible to heat stress. Instead, focus on consistent deep watering, mulching, and maintaining healthy soil until temperatures moderate.
Healthy Soil Is the Best Fertilizer
Healthy soil provides the foundation for healthy plants. Incorporating compost, maintaining organic matter, and encouraging beneficial soil microbes improve nutrient availability naturally. Organic amendments such as compost and well-aged manure release nutrients gradually while improving soil structure and moisture retention.
Let the Plant Be Your Guide
Plants often tell you when something is wrong. Pale green leaves may indicate a nitrogen deficiency, while poor flowering or fruiting can point to nutritional imbalances or environmental stress. Before reaching for fertilizer, consider whether heat, drought, overwatering, or compacted soil may be limiting nutrient uptake.
A thoughtful approach to summer nutrition combines proper fertilization with deep watering, mulch, healthy soil, and regular observation. By providing the right nutrients at the right time, you'll help your garden produce vibrant flowers, flavorful vegetables, and resilient plants that can thrive throughout the growing season.
