Supplemental Fertilizers for Raised Garden Beds FAQs and Solutions

Supplemental Fertilizers for Raised Garden Beds FAQs and Solutions

There are various ways to provide nutrients to the plants in your raised bed garden. In part two, I cover the best organic ingredients for building healthy soil, and why it's important to focus on enriching your soil with nutrients rather than fertilizers. Soil ecosystems benefit the most from organic ingredients, and your plants benefit the most from a healthy soil ecosystem.

I've listed some of the different organic materials in part two, along with tips on how to choose and what to avoid. In general, using any of the ingredients on this list is a better long-term solution than simply adding fertilizer.

First question: how do you know what your soil needs and/or which ingredients to use in your soil? I highly recommend you start with soil testing - every 2-3 seasons. Soil tests are available through your local county extension office and are fairly inexpensive. They will tell you the pH of your soil and describe (or list) any nutrient deficiencies.

Second question: what do you do with soil test information? Start with a pH reading. For vegetables, the optimal pH is neutral (6.5-7.0). When your soil pH reading is above 7.0, it tends to be alkaline. In other words, the higher your soil pH, the more alkaline your soil will be. The lower the pH of the soil, below 6.5, the more acidic it is.

Some of you might be intimidated by the scientific numbers and jargon behind soil testing, but it's not as complicated as it sounds. A soil test is a valuable companion in your gardening efforts - it will tell you what you need to add to your soil to get it to its optimal neutral pH range.

By telling you about your soil's nutrient deficiencies, the test will also help you understand what you need to add to your soil—nitrogen, potassium, calcium, magnesium, and more—to create a thriving ecosystem for healthy plant growth.

The good news is that good compost -- all on its own -- will have a huge impact on your soil pH. When you add it to your raised garden bed using the method I describe in part two of this series, it will go a long way to help balance your soil chemistry.

In general, all organic materials will naturally shift your soil chemistry towards the neutral pH range. That means, your compost, your shredded leaves, your grass clippings, your wood chips...all of which are good for your soil pH.

Going a step further, the ingredient descriptions I provide in Part Two will help you identify good options for improving the nutrients that are missing or lacking in your garden beds as identified by your soil tests.

Third question: Will the nutrients you add to your raised bed garden run off faster than those you add to your basement bed? This is a possibility, depending on how you provide these nutrients and the quality of the soil in your bed.

A healthy, thriving soil ecosystem is the driving force behind maintaining optimal moisture levels. A rich ecosystem provides your plants with a moisture sweet spot - allowing adequate drainage while still maintaining adequate moisture.

For example, if you use water-soluble fertilizers; some of these fertilizers will seep out during natural soil drainage. How much seepage will depend on the overall health of the soil. Since healthy soil is most effective at retaining the right amount of water, it also does a better job of retaining water-soluble fertilizers.

For those interested in using an irrigation system to deliver fertilizer to a raised bed, you can certainly go this route. Just know that fertilizers delivered this way are water soluble - so more likely to leach out to some extent.

Maybe you don't want to think about the loss of any kind of water-soluble fertilizer -- even the smallest loss. I feel the same way. I like to take advantage of what I spend time and money putting in my bed - by adding those organic materials instead of water soluble fertilizers.

The organic components are released slowly and are insoluble in water. They dissolve through biological activity - microbial activity in healthy soil. Healthy soil ecosystems process organic nutrients more efficiently - giving plants what they need when they need it. In other words, the organic material I add enables my soil to provide a kind of plant concierge. "Need nitrogen up there? At your service, for your needs."

Because I feed the soil this way - building it slowly with organic material over time - I rarely need supplemental fertilizer.

There are a few exceptions. One of them is that I decorate my raised bed once or twice a year before the growing season (I'll tell you about the second part again), and I usually add a little opener at a slow-release, non-synthetic pace , nitrogen based fertilizers - such as Milorganite. Alternatively, you might want to check out other good organic fertilizer options.

During the growing season, I sometimes add some organic fertilizer, like tomatoes, to the heavy feeder. For those greedy guys, I'll offer fish emulsion or other organic fertilizer twice (maybe three times) this season. That's it. Everything else my plants need is already in the soil bed because I design a healthy ecosystem by starting with the right soil "recipe" base and modifying it with organic materials.

This is why I love raised bed gardening. Yes, I can build an ecosystem of underground beds - I did, in the landscape of my garden farm. But with raised bed gardening, I have maximum control over the soil health of the bed.

My crop success is a testament to my efforts, and so can you.

Do you have earthworms in your garden bed? you should. This may not be news to you, but you may not know how to best get these worms in there in the first place.

The old adage "build it and they'll come" usually applies to earthworms too - especially if you create the soil types described in this series. Worms love it!

Here's another surprisingly easy way. If you add fresh worm castings (aka worm castings, aka worm droppings, aka one of my top organic ingredients listed in part two of this series), you are adding worms.

Worm eggs will appear in vermicompost and are a great way to fill garden beds. (Note that eggs may be killed during shipping of commercial worm castings, so fresh castings harvested from your own vermicompost bin will most likely have live eggs.)

You can add worms directly, as many gardeners do. Unfortunately, if the soil temperature drops below freezing, the worms die. Those who didn't die have gone deep into the soil surface (probably under your raised bed) in order to survive. Worm eggs survive the freeze and hatch and fill your garden bed in the spring.

Another Note About Supplemental Nutrients

Many people specifically inquire about the availability of supplemental nitrogen. Nitrogen boosts foliage - not fruiting (actually, at the expense of fruiting). If you've ever grown plants that looked good -- green and lush -- but produced a lackluster crop, look at the nitrogen levels of any fertilizers you add. Most likely you have added too much nitrogen to your soil.

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