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4 Fertilizers for a Healthy & Productive Container Garden

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Container gardens have special needs when it comes to fertilizing. Here are 4 natural & organic fertilizers to help you grow a healthy, happy, & productive container garden…

Fertilizer is important for healthy and productive plant growth, and plants grown in containers are no exception. In fact, container garden crops have special fertilizer needs that you need to be aware of.

For one thing, some fertilizer will wash out the bottom of the pots whenever the plants are watered, which means they will need regular additions of nutrients – more so than they would if the same plants were planted in the ground.

Also, some components may build up to unhealthy levels in the soil over time, since the soil in the containers is static and is not being churned and moved around by earthworms and other soil organisms. It is important that you use organic fertilizers in the correct concentration to avoid this issue.

There are 4 main categories of fertilizers that you should consider using on your container garden when growing vegetables and herbs in pots. If you are just wanting a very basic approach, however, you can probably do fine with most plants by using a basic, organic liquid fertilizer every other week. However, if you are growing larger plants with greater nutrient needs (i.e. tomatoes, peppers, etc.), you may want to go ahead and use all 4.

Here are the 4 main categories of fertilizers and supplements to use in your container garden:

  1. Liquid fertilization
  2. Liquid supplements
  3. Granular fertilization
  4. Granular supplements

An ideal fertilization regimen for container garden plants would include all four of these categories. If you have a special baby in a container, do all four. Your plant will thank you for it.

An advanced schedule for special plants would look something like this:

  • At planting: Granular fertilizer and granular supplements
  • Week 1 after planting: Skip
  • Week 2 after planting: Liquid supplements
  • Week 3 after planting: Liquid fertilizer
  • Continue to alternate a week of liquid supplements and a week of liquid fertilizer until fruit set, then:
  • At fruit set: Granular fertilizer and granular supplements
  • Week 1 after fruit set: Skip
  • Week 2 after fruit set: Liquid supplements
  • Week 3 after fruit set: Liquid fertilizer and liquid supplements
  • Continue applying liquid fertilizer and liquid supplements each week until the end of the growing season.

Any time I’m applying a lot of fertilizer and supplements, as in the example above, I cut back on the dilution strength of the liquids and the volume of the granular. The general idea is to give less, more often.

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Liquid Fertilizers

Fish emulsion is the best option I have found, no question.

It comes labeled with many different names like “Liquid Fish,” “Organic Fish Concentrate,” and just plain old “Fish.” As I understand it, fish emulsion is basically just a by-product of commercial fish processing—it’s the rest of the fish, liquefied in a blender.

Fish emulsion typically analyses at 5-1-1, N-P-K. So, it’s great for growing your plants large, and great for leafy green growth (lots of nitrogen). But, you’ll want to add a phosphorous source for vigorous root growth, budding, and fruiting. Or a potassium source for plants with general health and growth issues.

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My favorite solution for a liquid organic fertilizer is a locally made blend that includes fish emulsion, liquid seaweed, humic acid, molasses, fermentation extracts, magnesium chloride, iron sulfate, zinc chloride, and water. This product is labeled as 3 – 1.5 – 2, N-P-K. I have used this solution on a huge variety of plants, with good success and no burning,ever.

Dilution

Any product that you buy should have instructions for diluting. Follow the manufacturer’s instructions to dilute the concentrated fertilizer—never apply directly without diluting.

A common dilution rate is 1 ounce (2 Tablespoons) per gallon. If my label has worn off, or someone gave me a sample with no instructions, that is the dilution rate I normally use.

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Application

The correct amount to apply per plant should be given by the manufacturer, either on the product’s label or on the manufacturer’s website.

If they do not supply this information, a rule of thumb I use is to apply one ounce of diluted fertilizer solution per gallon of soil in the container.

So, a 1 gallon pot gets 1 ounce from the watering can. A 5 gallon pot gets 5 ounces, and so on.

For very small containers, I just give a quick splash…

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Liquid Supplements

What defines a liquid fertilizer is that it has a significant concentration of three key macro nutrients required for plant growth and fertility—nitrogen (N), phosphorus (P), and potassium (K). These three macro nutrients are key to growing healthy plants, but there are several other things you can do to help your plants grow big and strong.

These supplemental products include other macronutrients, lesser-known micronutrients, beneficial trace minerals, beneficial fungi, natural enzymes, living microbes, and a whole slew of other goodies.

Seaweed is like magic for some plants.

It doesn’t have high concentrations of the three key macronutrients—Maxicrop’s popular seaweed product analyzes at 0-0-1. But seaweed is great for heat and drought resistance, and it helps with many common problems.

If your plants are suffering from chlorosis, with yellow leaves and poor growth, seaweed can get them back to green and growing quickly (although you may be overwatering, so be sure to address the root problem)…

Using aerobic compost tea is a little bit like cheating. You take water that contains thriving colonies of microscopic life, and pour it onto your garden soil.

This is an especially effective tactic for containers, where the normal soil biology likely doesn’t exist yet.

You can inoculate the soil with many desirable microorganisms by applying aerobic compost tea. You can brew this miracle tonic yourself at home, or you might find an organic garden center nearby that offers it for sale by the gallon. If there is an active garden club in your area, ask around and find out if anyone else is sharing their brew or can show you how to make it yourself.

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Granular Fertilizers

Granular fertilizers are generally stronger and longer lasting than liquid fertilizers.

As always, a good rule of thumb is to stick with products that have single-digit concentrations of the three key macronutrients—nitrogen, phosphorous, and potassium. You’re still looking for something like 4-4-4, not 20-20-20 (N-P-K).

You will find granular fertilizers made from an assortment of different ingredients—mostly animal poop.

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My favorite granular fertilizer is a local product that analyzes at 8-2-4 N-P-K. It is made from feather meal, turkey compost, sulfate of potash, and molasses. Most plants use the basic macronutrients at the ratio of 4:1:2, so it’s handy to have a good all-purpose fertilizer like this that can be used on everything from the lawn to flowers to the vegetable garden.

Application

Applying granular fertilizers to your container garden is easy. Because these fertilizers are stronger and last longer, you will probably only need to apply these once or twice over the course of a growing season.

For the first application, at planting, I mix the recommended amount into the potting soil that I will use to fill my container.

Follow the manufacturer’s recommendation for how much to use. If no recommendation is given on the product packaging, I use one large handful for a 5-gallon container, and adjust proportionately for smaller or larger containers. In the bottom of the planting hole, I sprinkle another teaspoon or so of fertilizer, for immediate availability to the plant’s roots.

Be sure to mix the fertilizer well into the potting soil, so that it is evenly distributed throughout…

Sometimes I will come back with a second helping of granular fertilizer, either at fruit set or when I notice that a plant’s growth has slowed down significantly.

For the second application, I don’t dig down into the soil—I don’t want to damage the existing root system. I evenly scatter the granular fertilizer over the top of the soil in the container. Then I “scratch” the fertilizer down into the top 1 or 2 inches of the soil. Sometimes I use a hand rake to scratch the fertilizer in, but I usually just use my fingertips.

After the fertilizer is scratched in, give the container a thorough watering to activate the fertilizer…

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Granular Supplements

In addition to the three key macronutrients, there are lots of beneficial soil amendments that you can mix in to your potting mix at planting time.

Mycorrhizal Fungi

Mycorrhizae are fungi that have a symbiotic relationship with plant roots… As the fungus collects nutrients from the soil, it passes water and minerals up to the plant’s roots…

Mycorrhizae exist naturally in healthy soil in the ground everywhere, but not necessarily in potting soil. There are several products available from garden centers and online that allow you to inject these fungi into your potting soil. You can also get soluble mycorrhizae that can be watered into the soil.

Trace Minerals

While N, P, and K are the three big nutrients required for plant growth, there are many other nutrients that contribute to a plant’s overall health…

To round out your plants’ diets, you can add mineral sand to the potting mix at planting time. I use a mineral sand product that includes decomposed granite sand, lava sand, granite sand, basalt, soft rock phosphate with colloidal clay, humate, greensand, and montmorillonite.

Read more at TheGrowNetwork.com

 

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