The Time To Side Dress Plants With Organic Fertilizer Is Now

We’re now well into the prime growing season for both vegetables and ornamentals. Mother Nature seems to be providing adequate water, and while we had some June weather in April and April weather in June, the heat seems to be back on. Now there is one matter that needs tending too: feeding these rapidly growing plants.

An adequate supply of nutrients is extremely important now because the spring rains and any additional watering are leaching some of the nutrients out of the soil and the plants are using up the balance. To assure floriferous flowers and abundant veggies, some of these nutrients need replacing.

Some gardeners approach this problem by incorporating time-release fertilizers into the soil or planter at the beginning of the season and need not worry about further feeding unless minor supplemental feeding is needed. Others apply a granular fertilizer at planting time and then supplement this through the growing season with occasional applications of liquid fertilizers such as fish emulsion, kelp extracts, compost tea products or chemical fertilizers like Miracle-Gro, which is absorbed by both the foliage and root system. There is, however, a third alternative for feeding established plants and it’s called side dressing. It’s easy, and the results will benefit most plantings for 30 to 60 days depending on the weather.

Organic fertilizers are always preferred for this method because organics are much less likely to quickly leach from the soil in heavy rains, and they rarely burn plant roots. Chemical fertilizers are simply quick shots that don’t last. They can severely burn roots and foliage in hot weather as well.

Crops that especially “like” side dressing are the modern bedding annuals (they are often referred to as “hungry” and include but aren’t limited to geraniums, petunias, and verbena), hybrid roses and vegetables such as tomatoes, peppers, eggplants, cucumbers and other vine crops. For sweet corn it’s practically a must.

Cucumbers will give you a hint on when to side dress them, as will some squash and melons. The plants seem to stand straight up and just begin to blossom.

This is the time to side dress because you can still get within 4 to 6 inches of the stem. If you don’t side dress at this time, the next time you see the plant, it will probably be lying down and running its vines along the ground. Your chance to get close enough to the stem and near the feeding roots will be lost. However, you can still side dress when the vines are on the ground by simply lifting them aside. The fertilizer should not be placed at the stem but several inches away and never on the foliage.

Onions, especially, benefit from side dressing. If you side dress them when they are about 6 to 8 inches tall and then again when they are a foot or so high, they will produce high-quality, big bulbs. A balanced fertilizer with a ratio close to 1-2-2 is probably the most effective route to go, and this formulation will do well for both veggies and flowers, though flowers might prefer a ratio of 1-2-1. Remember, though, that if you are using a chemical fertilizer like 5-10-5 it’s high in salts and overdoing it will burn the roots. Be conservative (go organic) unless you’re an experienced gardener.

You can also use organic materials like bone meal, cottonseed meal, compost, dried or well-rotted manures, teas or any of the newer organic fertilizers, but remember that organic fertilizers release their nutrients somewhat slowly. Keep in mind also that the organics are much safer because they can’t burn like straight chemical fertilizers and organics are naturally timed-release. I’d save liquid, chemical fertilizers like Miracle-Gro for those plants that need fast responses, but you can be even safer when using liquid chemical fertilizers by cutting your rate of fertilizer added to a gallon of water in half.

Fresh manure should never be used as it may burn the root system and contain harmful pathogens. Compost teas in various forms are the new kids on the block, and they can act as effective nutrients. Biostimulants are not fertilizers, but they can result in better fertilizer uptake.

To side dress single plants such as tomatoes, peppers, eggplants, or a hill of plants such as melons or cucumbers, circular side dressing is the easiest method, and it works the best. Dig, spade or trowel a circular trench 1 to 3 inches deep about 4 to 6 inches away from the stem of the plant (at the drip line of ornamentals such as roses). You can also add the fertilizer to the top of the soil and then use a cultivator to work it into the soil. Organic fertilizers need to be mixed with the soil to ensure that the soil microbes can break down the fertilizer. If you are using liquid organics, manure tea or compost tea you can simply make your application on and around the plants without the need to do any digging, trenching, or covering.

To side dress crops planted in rows, dig a trench 1 to 3 inches deep along either side of the row, again at the leaf drip line. Sprinkle a band of fertilizer in the trench, usually using 2 cups per 100 running feet of row. If using composted manures, lay the manure about 1-inch deep along the trench. Cover with soil.

With both techniques, circular or row, you must be careful not to place chemical fertilizer too close to the roots or on the leaves of the plant because it can burn both foliage and sensitive root hairs. If using a high analysis liquid fertilizer such as Miracle-Gro, never make your applications on very hot days or in full bright sunlight in the heat of the day. The best time to apply chemical liquid fertilizers is early in the day or late in the day when the sun isn’t at its strongest. With aged manure, bone meal or cottonseed meal and the blended organics, you never have this problem.

You’ll find a myriad of organic fertilizers at local garden centers. Some have fancy and creative labels and earthy-sounding names. The bottom line is that for the most part your plant couldn’t care less. The marketing is mostly to influence you and has little to do with the effects on plant growth.

Now, in addition to giving your garden plants the additional nutrition they need at this time of the year, you should consider making your garden work hard for you by using the gardening space wisely. Many garden vegetables and some annuals are called “short season” because they mature in 30 to 60 days after they’ve been planted. Some of these are the dwarf marigolds and zinnias as well as leaf lettuce, radishes, beets, beans, peas, carrots and spinach. Once you’ve finished harvesting or enjoying the flowers, don’t delay pulling out the faded plants. Plant another short-season crop that you’ll be able to harvest in the fall and thereby double the yield of the same piece of land.

Some other short-season crops, such as early cabbage, cauliflower and loose-head lettuce are set out as plants but not for another month or so. Many of these are ready for harvest only a month or two after they’ve gone into the garden. After you harvest a cauliflower or head lettuce, pull up the whole plant and put the unused parts it on your compost pile. Then, spade up the soil, add fertilizer and plant something else in its place. You can put in another short-season vegetable transplant, a few onion sets, some carrot seeds or even some fall-blooming flowers or fall vegetables. Use anything that strikes your fancy, as long as there are enough days left in the season for whatever you plant. Head lettuce can grow among broccoli or marigolds with the cabbages making a handsome garden patchwork quilt. Keep growing.

When using insecticides on your property you should always be aware of the unintended consequences of these applications. It’s a common misconception that organic insecticides are “safe,” but I would say “safer.” Every organic insecticide I use — pyrethrin, Spinosad and neem oil — have label cautions that they can be toxic to bees. The suggestion is that you should only apply these to plants that bees visit early in the morning or late in the evening when the bees are inactive or less active. But when is that?

Before we get to the timing, keep in mind that we are not just talking about honeybees. The bumblebee and several other species of bees are important pollinators and should be welcome and protected in our gardens and orchards, not just the honeybee.

According to Emma Walters, the senior honeybee extension associate at Cornell, honeybees use temperature and daylight as their forage cues, and they typically forage on sunny to partly sunny days when temperatures are above 50 degrees. They use the sun to navigate so they only forage during daylight hours and return to their hives before dusk. So spraying should be done early in the morning or at dusk — not late afternoon.

Bumblebees, however, march to a different drummer. She refers to them as “heartier” and notes that they can continue to forage even on wet or overcast days.

I’ve been trying to grow Spigelia marilandica, also known as the Indian pink, since 2013. I’ve bought it at garden centers and even at a home center. I also bought a plant from Plant Delights and none of them overwintered. Not a gardener who easily gives up, last year I bought a named variety, Little Redhead, from Plant Delights and I’m pleased to say that all five of them, planted in two different locations, are thriving and were in full bloom in late June. A short perennial, growing only to about 18 inches, the flowers are striking and an eye catcher. It does well in moderate shade, attracts hummingbirds and tolerates wet soils.