As you nurture your plants along from seedling to full-grown plant, your plants may encounter some rough spots or bumps along the road. You can help your plants along and encourage them to grow bigger and stronger with a little foliar feeding.
Why foliar feeding?
The leaves of plants are amazing things. Their primary function is to take sunlight and convert it into sugars that the plant uses as food. But leaves also take in and regulate moisture for the entire plant. If the leaves are healthy, chances are the rest of the plant will be as well. So when you feed the leaves, you are feeding the whole plant.
Perhaps (hopefully) you have my eBook on starting plants from seeds. There you’ll see how I like to feed my seedlings to get them off to a good start. When you start from seed, the first leaves to emerge are the cotyledon leaves and they are similar to the size shape of the seed. At this point both the leaves and the roots are nourished by the nutrients in the seed itself. These leaves do not process light or other nutrients for the plant. But in a few days, the true leaves will emerge. They look more like the leaves of a mature plant and you can begin to identify the plant by its true leaves.

The true leaves can use photosynthesis and the nutrients from the soil to feed the plant. So after there are 4-5 true leaves, you can begin spraying a foliar fertilizer. Be careful not to overdo it. Like feeding too much fish food in a fish tank, unused fertilizer will just sit on the soil and harbor mold and bacteria.
But the time the plants will really benefit from foliar feeding is during times of stress, when the roots aren’t able to nourish the plant very well. Spray your plants with a foliar fertilizer after you transplant seedlings to a larger pot or into the garden. If you’ve had a few days without rain or water, spraying the leaves with a feeding solution will help the roots take up the water from the ground more readily.
Easy does it
Now, the leaves are limited on how much nutrients they can take in. Too much fertilizer will create mold or scalding spots on the leaves, so a little goes a long way. Use a very diluted fish emulsions, liquid comfrey fertilizer, compost tea or a commercial liquid fertilizer. If you use liquid fertilizer, dilute it 1/4 to 1/10 what the package directs.
My personal favorite is my own homemade foliar fertilizer. It costs just pennies to make two gallons. In fact, I bought a one-quart bottle of fish emulsion and I’m still using it five years later!

My homemade version has more nutrients for root growth than a compost tea or some commercial fertilizers have, so I only use it when roots need an added boost but I quit using it when the plants are ready to blossom or get leafy.
When you spray, make sure to spray the underside of the leaves, because that’s where the stoma (the cell openings that take moisture and nutrition in) are. Also, it’s best to feed in the early morning or late evening hours when the stoma are more open. The stoma close up during the heat of the day to keep from losing too much moisture.

One more reason
I save a lot of money on plants by buying them late in the season. “Why,” you may ask “Why would you want to buy plants from the nursery when you start so many from seed?” Well, because no matter how many plants I start from seed, there always seems to be some empty spaces that need filling in. Or sometimes there are plants that die after transplanting in the garden leaving an empty hole in the garden. Or, sometimes after.
After getting everything in, I look around and think “Hmmm….here are some pots that are begging to hold some lovely flowers.” So I go to the garden center and pretty much everything is picked over–the selection is limited and the plants are so battered and sun-weary, I know they’ll never find a good home if I don’t take them. And by then the prices are so ridiculously low, I really can’t resist. Sometimes the greenhouse manager is so
embarrassed at how bad the plants look they just give them to me.
So, I bring these sad-looking plants home and repot them. Then I cut off the top 1/3 of the plant. I cut that much off because usually it’s pretty battered and leaves are browned or torn. And it means that there is less to stress the roots to try to feed a larger plant. Then once the plant recovers from its rough start, it will grow out more vigorous and bushy. Then I give everything a good foliar feeding once a day for the first 2-3 days. A week or two later, all these plants have recovered and are on their way to being a beautiful addition to my garden.
On last note
There’s some debate about whether or not foliar feeding is really beneficial. But I’ve seen several studies that made me want to try it. My personal experience tells me it’s a good thing. I’ve been able to rescue a lot of plants from certain death and my seedling are a lot bushier and more vigorous when I feed my plants with a foliar feeding. Since it costs so little to do, why not try it?