Marianne's Response

Using Osmocote in Bottom-Watered Container

Living in Wyoming, I use bottom-watered containers in a greenhouse to grow vegetables and herbs. I add nothing to the water, only adding fertilizer to the potting mix. If I use Osmocote, how should I mix it into the potting mix and in what amounts? Top-dress, mix in top layer, or mix throughout? Each container is about 2 feet long, one foot wide and has 6 inches of potting mix. Each container has its own vegetable variety, so I can use different applications in each one. Do you have any guidance for me? I would be interested in application rates by volume of mix, and by plant type. I have purchased both flavors of Osmocote – Outdoor-Indoor and Flower-Vegetable. I assume my tomatoes and peppers are hungry for micronutrients which are probably not in potting mixes, so maybe the Indoor-Outdoor type would be best for them? I have found it necessary to apply a heavy dose of dolomite to last all season for all of my plants, but I need some advice on the slow-release component that I put in the containers. It’s time for me to put plants out, even though we had a blizzard last night. Thanks.

Posted by Robert Wells on April 17, 2020

Marianne's Response

Well good for you growing food despite your challenging Wyoming climate. Either type of Osmocote fertilizer can be used on your edible crops and you do not need a different type for different crops. The best way to mix in the granules is to measure according to the package instructions, sprinkle the amount on top of the soil then dig this into the rest of the soil so that the Osmocote is mixed throughout the potting soil. Both types of Osmocote has the micro nutrients your plants need. A complete fertilizer  like Osmocote is simple to use because the plants take only what they need and an entire menu of macro and micro nutrients is offered to them in a slow release form. This means you only need to fertilize once every six months or one growing season. Looks like you will be enjoying a bountiful harvest this summer. Keep growing, Marianne Binetti

    Search the Ask the Gardening Expert library

    Looking for a quick resolution to your problem? Marianne has answered thousands of gardening questions. One may be similar to yours. Try searching our library to get the answer you need — fast!

    My Topics

    View questions you submitted to Marianne in the past

    VIEW MY QUESTIONS