Understanding Types of Fertilizer for Your Garden

Slow-Release Fertilizer

Slow- or gradual-release fertilizers are ideal for quick-color plants. Special coatings release nutrients over three to nine months—check the label for the exact timeframe. Many bagged potting mixes already include slow-release fertilizer. If yours doesn't, mix it in before planting. Mid-season, you can work more into the soil if needed.

Soluble Fertilizer

Dissolved in water, soluble fertilizers provide a quick nutrient boost. They're easy to handle, store, and contain high nutrient concentrations. In soil rich in organic matter, nutrients are retained; in sandy soil or soilless mixes, they leach quickly with watering. Most are applied to soil, but some are foliar sprays absorbed through leaves.

Organic Fertilizer

Organic options like compost and manure supply slow-release nitrogen, improve soil structure, encourage beneficial microbes and earthworms, and provide essential micronutrients. They're best for planting beds or large containers like half-barrel planters.

Concentrated organic meals (bone, blood, cottonseed) offer a big nutrient punch in small amounts, hence higher cost. They require microbial breakdown, so they're less effective in cold weather when microbes are inactive.

Recognizing Nutrient Deficiencies

Plants signal when nutrients are lacking:

• Nitrogen deficiency: leaves turn yellow.
• Phosphorus deficiency: leaves turn reddish or purple.
• Potassium deficiency: older leaves burn and drop.
• Other signs: weak/slow growth, smaller leaves and flowers.

How to Apply Liquid Fertilizer with a Hose

Attach a siphon device to your faucet, mix fertilizer concentrate in a bucket, and the water flow dilutes it automatically as you water.

Fertilizer Retention in Containers

Container material affects watering frequency, which directly impacts nutrient retention. Frequent watering (from rain or irrigation) washes nutrients away faster. Less frequent watering retains nutrients longer.

Terra-Cotta Pots

Unglazed terra-cotta is porous, allowing air and water movement. Good for plants that prefer dry soil, but it requires more frequent watering, which leaches nutrients. Fertilize plants in these pots more often.

Plastic Pots

Plastic isn't porous and retains water longer—ideal for moisture-loving plants. Soil stays wet longer, so nutrients remain available longer.