Feeding tomato plants with liquid fertilizer

Healthy gardens rely on healthy soil, which contains a variety of beneficial microorganisms and nutrients that help plants thrive. To improve soil health, organic gardeners may use an array of natural fertilizers, including manure, compost, bat guano, worm castings, rock phosphate, bone meal, and seaweed. While effective, these fertilizers can be slow to release the nutrients the plants need. In recent years, liquid fertilizers have grown in popularity partly because plants can absorb nutrients more quickly in liquid form. In addition, liquid fertilizers can increase crop yields and be applied directly to plants’ leaves, which facilitates fast absorption.

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Liquid Fertilizers for Organic Gardeners

These fertilizers are an excellent option for trees, shrubs, lawns, flower beds, and vegetables alike.

Packaged Liquid Fertilizers for Home Gardens

Some of the most popular organic liquid fertilizers include fish emulsion and seaweed fertilizers, which are diluted and used to irrigate plants or spray the leaves. Certain liquid fertilizer manufacturers have products available for specific applications, such as lawn care products that can attach to the garden hose or tomato formulas that are high in the nutrients they need to produce a bountiful yield.

DIY Liquid Fertilizers for Home Gardens

Some organic gardeners make homemade liquid fertilizers using ingredients such as finished compost, animal manure, seaweed, and even garden weeds. The exact approach often depends on what ingredients are locally available. These products usually take between a few days and a month to make and involve adding water and solid ingredients into a bucket or container, stirring it regularly, and filtering the liquid. Dilute the final product before applying it to gardens.

Home DIY liquid fertilizers include compost tea, manure tea, a liquid fertilizer from weeds, liquid seaweed fertilizer, and even human urine. However, beware of applying manure fertilizers in a way that can spread pathogens to edible crops.

Applying liquid fertilizer to plant leaves
Some gardeners swear by foliar feeding, which allows plants to uptake nutrients from a liquid fertilizer through the leaves instead of the roots.

Advantages of Liquid Fertilizers

Although there are some advantages to liquid fertilizers, they aren’t intended to replace other types of garden amendments, like compost and powdered fertilizers.

Faster Nutrient Availability

The nutrients in liquid fertilizers tend to break down readily, making them available to the plant more quickly than solid fertilizers. This is especially helpful if you want to boost stressed or diseased plants that need nutrients immediately.

Foliar Feeding

You can apply liquid fertilizers to the soil so that plants can absorb nutrients by their roots. But some gardeners swear by foliar feeding, which allows plants to uptake the nutrients through the leaves instead of the roots. To foliar feed plants, apply a mist of diluted organic liquid fertilizer to the leaves of the plant — particularly the underside of leaves — using a spray bottle or garden sprayer. The ideal time is early morning when temperatures are still low. Many gardening experts recommend foliar feeding plants every two to three weeks.

Foliar Feeding Can Complement Healthy Soil

Foliar feeding can be an excellent approach to delivering nutrients to your plants. But don’t overlook the importance of healthy soil — it’s the foundation for a vibrant garden. Feed the soil with compost, mulch, granular fertilizers, and even cover crops to create a healthy balance of microorganisms. Adding organic liquid fertilizers during the growing season will  give your garden a boost.

Using liquid fertilizers is similar to taking high-quality dietary supplements for optimum health. Although supplements are helpful, they should fortify a nutritious diet, not replace it.

By Sarah Lozanova

Sarah Lozanova is an environmental journalist and copywriter and has worked as a consultant to help large corporations become more sustainable. She is the author of Humane Home: Easy Steps for Sustainable & Green Living, and her renewable energy experience includes residential and commercial solar energy installations. She teaches green business classes to graduate students at Unity College and holds an MBA in sustainable management from the Presidio Graduate School.