Contemplating summer season fertilizer on your backyard? Proceed rigorously, or danger doing extra hurt than good.

For some crops, midsummer fertilizing can present a wanted enhance after three months or extra of vigorous rising. However for a lot of others, fertilizer will be pointless and even dangerous.

“Solely fertilize crops if you happen to’re certain they want it,” mentioned Julie Janoski, supervisor of the Plant Clinic at The Morton Arboretum in Lisle. “Making use of fertilizer when it isn’t wanted or on the incorrect time, or making use of an excessive amount of, can dry out crops’ roots or create chemical imbalances.

“In the event you over-fertilize crops, you could get too many leaves on the expense of flowers,” she mentioned. Surplus fertilizer additionally finds its manner into rivers and lakes and causes severe air pollution issues.

Timber and shrubs not often want fertilizer. “We don’t normally advocate fertilizing them except a soil take a look at has proven a particular nutrient deficiency,” she mentioned.

Most perennials don’t want fertilizer both, so long as they’re planted in soil that has satisfactory natural matter. Organisms in wholesome soil will digest the natural matter to supply the vitamins the perennials want.

Which crops do want fertilizing? “It’s normally crops equivalent to flowering annuals which can be rising in unnatural circumstances, equivalent to containers, the place they’ll’t entry vitamins from a large space of soil,” she mentioned. “In these circumstances, they shortly burn up the obtainable vitamins, they usually can use some further assist.” A fertilizer enhance may also assist greens preserve producing via the harvest season.

Fertilizer is just not plant meals. Crops make their very own meals via a chemical course of known as photosynthesis that captures power from daylight. Fertilizer can complement crops’ meals with a rise in sure chemical parts they should construct massive molecules.

In nature, crops get all the weather they want from the soil. In our dwelling landscapes, which are sometimes very completely different from crops’ pure properties, sure crops might develop deficiencies that fertilizer can provide. For instance, if a pin oak tree is planted in alkaline soil somewhat than within the acidic soil this tree species prefers, it might develop an iron deficiency that may be helped by fertilizer. A bur oak tree, which is customized for alkaline soil, wouldn’t want it.

Listed below are some tips from Janoski for summer season fertilizing:

Use slow-release. Fertilizer formulation that dissolve slowly into the soil will launch vitamins progressively and keep away from overdosing crops. Natural fertilizers are all slow-release, as are some artificial formulation.

Test the ratio. The label of each fertilizer product has a ratio, equivalent to 3-1-1, indicating the odds it comprises of nitrogen, phosphorus and potassium, the weather that crops use within the largest portions. “Search for numbers within the low single digits, which point out that the product is a slow-release method,” Janoski mentioned.

Extra is just not higher. By no means exceed the quantities advisable within the instructions. “Err on the aspect of utilizing much less,” she mentioned. “In the event you’re utilizing a liquid fertilizer that’s dissolved in water, you may play it secure through the use of half the quantity advisable on the label.”

Water first. The chemical substances in fertilizer are principally salts and might simply dry out plant tissue. For insurance coverage, be certain that the crops are effectively provided with water earlier than you fertilize.

Apply on the proper time. Completely different crops may have supplemental vitamins at completely different occasions. Fertilizing in summer season may also help annual flowers preserve blooming till frost and preserve greens producing. Lawns, although, are finest fertilized in early fall, after they have begun rising once more in cooler climate, and the fertilizer may also help them develop sturdy roots. Within the uncommon cases that timber or shrubs want fertilizer, it’s best utilized in spring or fall. Ask the Plant Clinic for recommendation on whether or not and when to fertilize explicit crops.

Fertilizer is just not a cure-all. “The one factor fertilizer may also help with is a scarcity of explicit vitamins,” Janoski mentioned. “If that isn’t the reason for the issue, fertilizer will likely be ineffective.” All the time determine the rationale {that a} plant is just not rising effectively earlier than you resolve whether or not fertilizer is perhaps helpful.

Take a look at your soil. “A soil take a look at can inform you the chemical composition of your soil, that can assist you select crops which can be prone to develop effectively with out the necessity for fertilizer,” she mentioned. Be taught extra at mortonarb.org/soil-test.

For tree and plant recommendation, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant-clinic, or [email protected]). Beth Botts is a workers author on the Arboretum.