Instructions: How to Assemble your Jarrarium

After absorbing all that knowledge I just threw at you, you might feel daunted by the actual construction of a jarrarium. Fortunately, it really is quite simple. The whole process will take you a week or two, but only a couple hours of that is actual labor. Be sure to envision your goal before you start so you can prepare and assemble accordingly.

1. Gather materials

As is tradition, we start by gathering our materials. Everything you’ll need can be found in your home or very close by. You should almost certainly be able to complete this project without spending a dime.

  • Jar or similar vessel (can also use vase, fishbowl, old aquarium). The important thing here is that your container is transparent and glass. Bigger is better! Check thrift stores, they always have lots of these.
  • Substrate, the type of which depends on your jar. If you are emulating a pond, use pond mud. If you want to grow plants, you’ll need mud or soil capped with sand. Just plain old sand is an acceptable, neater option.
  • Water from a pond or cycled aquarium. You can also use water treated with neutralizing chemicals for fish tanks, but some amount of pond water is best.
  • Life – Jars can’t sustain vertebrates like fish, so do not put fish in your jar. Snails are, however, appropriate. You can also gather some aquatic plants from your pond if you want, or order them online.

2. Fill in substrate (and plant roots)

It’s time to pour into the bottom of your jar whatever you’re using for substrate. You generally want this ground layer to be about an inch thick. That provides ample room for the roots of any plants you have, as well as room for all of the invertebrates living in that substrate (if you used pond mud, you will have plenty).

If you decided you wanted to use soil + sand as your substrate, you will have an extra step. Put half an inch of soil, you can use regular potting soil, on the bottom. Use water (tap water is fine) to wet it so that the water level is just under that of the soil. Let it sit for a day, soaking up the water. This will prevent the soil from trying to float to the surface when you fill up the jar completely. If you have aquatic plants that need to be rooted, this is when you should plant them. It’s okay for them to be exposed to air for a day or two. After the soil is sufficiently soaked, carefully pour sand or gravel on top of it to create a cap about a half-inch thick. This separates the soil from the water, and should keep your water clean.

3. Fill in water

This part gets kinda tricky. While we already know that cloudy water isn’t harmful to a jarrarium, we don’t really want the water cloudy. When all that settles out it will be on top of your substrate. If you’ve just got mud, go ahead and pour your water with reckless abandon. Mud don’t care. If you have sand or gravel you want to look nice and neat, or you’ve already planted some stuff and don’t want to knock it loose, water can be dangerous.

There’s a couple of tricks to get around this though. Place a large rock in the center of your jar and pour directly on to it. Or, turn a spoon upside down and do the same. Both will serve to reduce the energy of the water before it hits the substrate. Tilting your jar to the side and filling it like a drink can work, if that doesn’t mess up your substrate.

Fill the jar near the top, but leave at least an inch. It’s important that there is exchange between the surface of the water and the air. If you have any additives to the water, like garden lime for calcium carbonate, it should be mixed in now. Finally, leave your jar overnight so everything can settle out of the water. It should be mostly clear by the following morning.

4. Set decorations and remaining plants

Whatever you chose to decorate your jarrarium with, be it natural or artificial, should be introduced to the jar during this step. There should be no significant disturbances to the jar for the remainder of the process.

Gently place decorations directly onto the bottom. Dropping objects in water tends to lead to unpredictable landings, so you’ll prefer to guide them all the way to the substrate. Cover the bottom with some substrate to anchor it if necessary. Or, use an aquarium weight.

Plants that are introduced at this stage likely have rhizomes that should not be buried, or are floating plants anyway. Plants can be secured to the bottom via aquarium weights, or you can tie them to objects like wood or rock before putting them in. Obviously, any floating plants like duckweed should be last.

5. Allow your Jarrarium to cycle

You should have chosen your cycling method before starting assembly (refer to the cycling section if you need a reminder). Generally, you should allow 2 whole weeks for cycling. During this time, the jarrarium should sit undisturbed in a place with moderate lighting. There are few, if any, outward signs that a jar is finished cycling. If you were to place a drop of water in a microscope on the day you assembled your jarrarium, you probably wouldn’t find anything. When a jar is fully cycled, however, that same drop of water will be flourishing with life.

If you are impatient, understandably so, you may be able to shorten this time. Using more than one method of cycling should speed up the process (i.e. build your jar with pond mud AND pond water). In this case, you may only need to wait a week.

The consequences of adding animals before a jar is cycled vary. The parameters of the water are likely still fluctuating, and it could harm or kill your animals. The added bioload of a few critters while the nitrogen cycle is still being established could lead to a collapse of your entire ecosystem! It’s best to give a jarrarium time to cycle fully to avoid any unnecessary danger.

6. Add animals

Reward your patience during the cycling phase by splurging on some cute invertebrates. Take a trip to the pet store or browse some online vendors to find a couple snails and/or shrimp. When purchased, they will arrive in plastic bags filled with water. They are undoubtedly quite stressed out by the transport and their temporary home, so you want to make their transition as easy as possible.

If possible, place the bag in your jarrarium on the surface for a couple hours. This will slowly change the temperature of the water in the bag to the temperature of your jarrarium. If it doesn’t fit, a similar effect can be achieved by setting the bag next to the jar in the same conditions for a while. When the temperatures are equivalent, slowly pour the water and the animals from the bag into the jarrarium. Don’t try to scoop them out or drain the water first, that will just bother them.

Don’t bother trying to feed them for a couple days. They will be traumatized from their move and are unlikely to eat. Additionally, in a cycled jar, there should be ample detritus for them to nibble when they get peckish.

7. Enjoy your Jarrarium

That’s it! You’ve made a jarrarium! No matter the style of jarrarium you constructed, you are sure to be entertained by the result. If you elected to create a sealed jarrarium, now is the time to close the lid. Good luck on your journey!

This step marks the beginning of your jar’s life. If you accepted the recommendations for plants and animals laid out in this guide, you should have a respectable low-tech jar. You shouldn’t need any filtration system or bubblers or extra lighting. Keeping your jarrarium in a window sill or near a light that is on all day should provide all the energy necessary to your system. Likewise, regular house temperatures between 67-74°F are ideal. Begin maintenance on your jar around this time as well.


Thanks for sticking it out to the end! If you liked the guide, consider buying the eBook to support the author, and to have this info with you wherever you go!

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