When and how often should you apply plant fertilizer: Tips, timing, more in Dan Gill's mailbag (2024)

FAQs

How often should I put fertilizer on plants? ›

It's typically recommended to apply fertilizer in clay soil about every four to six weeks after planting. For plants growing in organic soil that's rich with organic matter, only fertilize a little bit every three to four weeks.

In general, best fertiliser results are achieved by feeding three times a year – early spring, early summer (before it gets too hot) and mid to late autumn. If you are going to only fertilise once a year, do it in late spring to early summer.

Late afternoon or early evening (when there's still light, of course) is the best time of day to apply lawn fertilizer. Applying it in the heat of a scorching afternoon can cause the sun's rays to burn your grass—and when your goal is "lush and green," burned grass blades simply won't cut it.

It is generally recommended to split the fertilizer application so that half is applied at sowing and the other half 20 to 45 days after sowing, depending on soil moisture availability and type of crop. The type of soil is also very important in determining the time of fertilizer application.

Always follow the manufacturers recommended rates and application methods. Fertilize outdoor plants in the coolest part of the day, such as early morning or late evening, especially in hot summer weather. Always water in fertilizers well to distribute nutrients throughout the soil profile and to prevent burning.

Too much fertilizer (applied too often or too much) can burn or desiccate roots, ultimately killing the plant. Too much fertilizer can also be harmful to the environment. But, fertilizers do a lot of good by providing macro and micronutrients that enhance the health and performance of plants.

Granular fertilizers are generally applied about every six to eight weeks. Slow-release fertilizers work for months, so one application is generally all that is needed for a growing season.

Fertilizer and Water

A day or two before applying fertilizer, water your lawn thoroughly. After grass dries, apply fertilizer. Then lightly water again. This second watering is vitally important, because it washes fertilizer off grass blades and into soil.

If you use a slow-release fertilizer, it will take a little bit longer for them to start working, typically between 2-7 days. There are also slow-release organic fertilizers that are available, and they can take anywhere from 2-6 weeks to start working.

Ideally, you want to apply fertilizer treatments to your lawn after it rains. However, you'll want to wait for the puddles on your lawn to sink into the soil and the grass blades to dry. It's also a good idea to fertilize your grass if it is sunny for a few days after it rains.

Can you apply fertilizer too early? ›

To ensure your grass will be able to utilize the nutrients from the fertilizer treatment, you should wait until the soil temperature warms up to about 55 degrees Fahrenheit before applying it. To ensure you're not fertilizing your lawn too early, you should hire professionals to apply the treatment.

General tips. Avoid applying fertilizers when plants are dormant or under heat and drought stress. Fertilizers should be incorporated into the soil to prevent losses. If you cannot physically incorporate a fertilizer at this point in the season, it may be best to stick with a water-soluble fertilizer.

Best case scenario, this is the standard schedule your lawn needs: Mid to end of APRIL – spring fertilizer – 32-0-6 slow release (fast acting) Early to mid JUNE (6 weeks later) – early summer fertilizer – 25-0-5 – 50% slow release. Mid to late JULY (6 weeks later) – late summer fertilizer – 25-0-5 – 50% slow release.

One application every four to six weeks after planting is typically enough. Crops growing in organic soils may need little additional fertilizer—again, just use foliage color and plant vigor as guides.

Vegetable gardeners can fertilize their garden beds about once a month with a quick-release fertilizer or about once a season with a slow-release fertilizer. Some gardeners prefer to feed their flowers and plants with a liquid-soluble plant food once every one to two weeks.

Light green foliage and yellowing mature foliage can be a sign that a plant needs nitrogen. Chlorosis (light green leaves with dark green veins) can be a signal that a plant needs potassium. If older leaves are turning purple at the base and other leaves are dull, dark-green, there could be a deficiency of phosphorous.

Generally, you can fertilize your plants on a bi-weekly (every other week) or a monthly basis depending on the fertilizer you're using. Make sure to read the label provided, as the recommendations on dilution and timeline can vary by brand. Recently potted or repotted plants will not benefit from fertilizer.

Choose Your Feeding Style

Measure and mix it directly into your watering can and pour the solution around the bases of your plants, or use with your hose in a sprayer (like the Miracle-Gro® Garden Feeder) for larger areas. Plan to feed every 7 to 14 days.

You should water granular fertilizer immediately after it is applied to your plants. Granular fertilizer needs the help of water for it to activate, so it will have no effect on your garden if you forget to water after adding it. For liquid fertilizer, you should wait longer before watering your plants.