Gardening: Foliar feeding can help new growth weather the weather

Nancy Szerlag
Special to The Detroit News
Kelp contains 60 or more trace minerals along with nutrients that when used as a foliar feed are ready for a plant to use.

While established perennials --  though slow in starting -- are doing well this year, enjoying all this wet weather, newly planted plants are suffering incredible stress. Transplant shock is always a problem, but the sudden fluctuations in temperatures after planting have also been a big issue. 

If your garden is in the vicinity where liquid applications of herbicides and pesticides are used, that also may be part of the mix.  When applied on a windy day, wind drift can be an unseen carrier of damage and death. 

Drought is another common cause of plant stress, but this year prolonged rain fall and flooding are the big villains.  Malnutrition is an issue for plants fertilized with water-soluble chemicals that are quickly washed away in the rains. 

If you’re looking for stress relief for your plants, you may want to consider foliar feeding them with liquid kelp every couple of weeks.  When foliar feeding you apply liquid fertilizer directly to a plant's leaves. 

Kelp contains 60 or more trace minerals along with nutrients that when used as a foliar feed are ready for a plant to use.  Kelp also contains macro-nutrients valued as a growth stimulant, potent concentrations of trace minerals, micronutrients, amino acids and vitamins as well as many growth hormones, including cytokinins, auxins and gibberellins, which stimulate cell division and larger root systems. 

Researchers discovered kelp helps build and support a plant’s natural immune system to resist  disease, insects and heavy temperature swings.

Soaking seeds in liquid kelp improves the germination and the strength and vitality of seedlings. It’s also said to improve the germination rate of older seeds that may be past their prime. 

According to research at Clemson University, foliar seaweed sprays increase the yield of tomatoes. 

Kelp also improves the water holding characteristics of soil and helps the formation of crumb structure. 

A foliar application of a gentle fertilizer such as fish and kelp or seaweed mixed at a rate of 1 tablespoon per gallon may help these plants to “buy time” until the temperatures normalize, the sun shines and they can photosynthesize and make their own food.  

When spraying, apply until the foliage is completely wet and be sure to hit the undersides of the leaves. Foliar feeding should be done in the morning (before 10 am.) or in the evening, just before sunset. But it can be done anytime on an overcast day. Adding a spreader sticker, available at garden centers, helps the product adhere to the leaves and makes it work better. A teaspoon of Dawn dish soap per gallon of diluted fertilizer will also work. 

Nancy Szerlag is a master gardener and Metro Detroit freelance writer. Her column appears Fridays in Homestyle. Email her at, Ask Nancy.  You can also read her previous columns at