Is there a way I can make transparent soil for plants at home?

Question

I want to observe root development of plants for a hobby home experiment. I need transparent soil for this purpose.

I asked some local gardening stores for it, but they said that they don't sell such a thing. Is there any way which I can make it myself at home with as simple materials as possible?

Requirements:

• It must be very transparent if not completely.
• It mustn't contain any ingredients that would harm plant roots.
• It must be able to carry oxygen from air to the roots of the plant.
• It must be able to hold water in it, and supply it to the roots.

Answer 1

You can search for polyvinyl alcohol granules. They often have pigment mixed in, but polymer itself does not have any color, is transparent and keeps big amount of water. You also can consider avoiding usage of soil at all as some plants grows well in pure water without soil.

Answer 2

Transparent glass beads or marbles in a transparent glass would do the job. Many plants will do quite well in water. The beads are for mechanical support for the stem.

You might find algae will become a problem as it too will grow in water. Flushing with fresh water on a regular basis and keeping the container out high light will control this.

Edit This recently published study covers exactly what you are asking for. The researchers used

Nafion, the building block of transparent soil, is a transparent ionomer (synthetic polymer with ionic properties) that is physically and chemically adaptable. Nafion particle size distribution has been manipulated by freezer milling (250–1600 µm).

This product appears to be available at chemical supply houses but might require some processing. It is described as

suitable for growing and imaging the roots of various plant species, including alfalfa, barley, maize (data not shown), tobacco, lettuce and thale cress (Arabidopsis), and imaging at the whole root level can be achieved using OPT (Fig. 2A). Transparent soil provides images with low levels of noise and opens avenues for automated analyses of genetic screens.

Answer 3

Kevinsky might have the right idea. However, the Nafion polymer referred to in that PLOS article might be overkill. It's priced at ~$5.00/gram which might be more than someone would be likely to want to spend for an interesting graphic experiment to show their friends (and this is without even going into the additional processing to make it more soil-like as described in the journal article cited).

While having something closely resembling soil is useful for researchers interested in knowing what happens in real soil, plants do not need such a good soil simulacrum to actually grow well; and, as Ben Norris has pointed out, many will even grow very well without any soil or support of any kind at all.

If it were me, I, like permeakra, would try using something like polyacrylamide hydrogel beads which will be orders of magnitude cheaper than the Nafion beads. I would probably also do some sort of processing to achieve a smaller particle size than the sizes you are likely to get easily (the researchers in the article which Kevinsky cited did this as well).

This won't necessarily result in a fully viewable, transparent growth medium, though. To achieve that you will need to fill your growth container to the top with the irrigating solution to eliminate all air spaces. The similar refractive index will make the fully hydrated hydrogel particles nearly invisible (the researchers in the article which Kevinsky cited further adjusted the refractive index of the solution using sorbitol or percoll to better match the refractive index of the beads they used but this will probably be unnecessary with the cheaper hydrogel beads and for this application).

Having the growth medium waterlogged may work with some plants but not with others (because roots generally need oxygen). In the latter case I can think of two solutions to deal with this issue:

• Constructing a hydroponic circulating system which aerates your nutrient solution (so the water level is always high but there's enough circulation to prevent a hypoxic root environment).
• Living with the fact that the medium is not transparent and keeping it in a container with a drain hole. One could plug the drain hole and add water whenever one wished to visualize the roots (which is what the researchers in the article cited by Kevinski actually did).

Also, you might be interested in having a mechanism in place set to block light to the root area when not viewing the roots since it may affect some plant roots and, as kevinsky pointed out, will promote undesired algal growth.

Answer 4

I have had a lot of success transferring my indoor plants to hydroculture. Bamboo, aechemia fasciata (silver vase or urn plant), aloe vera, hippeastrum (commonly sold as amaryllis), and araucaria heterophylla (norfolk pine) have all thrived in plain water, sometimes with rocks or marbles added for support, and provide a very nice view of the roots. I have, however, noticed that the water roots look slightly different than the soil roots (which die off eventually after being transferred to water, being replaced by the roots adapted to the water environment), however, the growth pattern of the roots seems unchanged.

As mentioned above, the water needs some circulation to keep it oxygenated, both for the plants' health and to prevent stagnation of the water. For very thirsty plants, this is achieved simply by topping up the water level with a watering can when it gets low, with plants that do not drink as much, I occasionally need to dump the old water before adding more.

Answer 5

There's a product call gel 2 root which is a clear cup with a clear gel in it that you can use to root cuttings of plants. I'm not sure how it would work if you tried to start seeds in it and keep the plants growing, but for cutting this would be a good way to see the root structure as the plant grows.

Answer 6

Something like this maybe https://www.seedman.com/plantge.htm It's "plant gel" I've bought some plants that came in it.

Answer 7

A technique that works well for large seeds like beans is to take a mason jar, then line it inside with a cylinder of light coloured blotting paper from the bottom up to the neck of the jar. Then fill inside the cylinder with an absorbent material such as damp peat. Using a spoon, take the bean seed and insert it in between the paper and the glass wall of the jar, about halfway down. The blotting paper will soak up moisture from the peat, and the bean will sense this and start to swell and germinate.

Maintain the moisture in the peat; keep an eye on the water level at the bottom of the jar, and resist adding more water if you see clear water forming at the base of the jar. The radicle quickly appears and is followed later by the top growth. It's a cool and reliable experiment for classrooms and such, requires little attention and lasts as long as the stored food in the cotyledons of the bean.

Answer 8

Clear absorbent beads will do. Cheapest supply get a used nappy from a baby. can also use "proper" gel product used for adding to soils.

Answer 9

Yes, it is possible to create transparent soil for plants at home using a few different methods. Here's one approach you can try:

Materials needed:

1. Clear acrylic or glass container with a lid
2. Silica gel or fine sand
3. Potting soil or compost
4. Seeds or small plants

Instructions:

1. Clean the acrylic or glass container thoroughly to ensure there are no residues or contaminants.
2. Fill the container about one-third full with silica gel or fine sand. This will provide the transparent medium for the roots to grow through.
3. Add a layer of potting soil or compost on top of the silica gel or sand, leaving enough space for the plant's roots.
4. Plant your seeds or small plants in the soil layer, following the recommended planting depth and spacing for the specific plant species.
5. Water the soil lightly, ensuring not to disturb the silica gel or sand layer below.
6. Place the lid on the container to create a controlled environment for the plants.
7. Position the container in a location that receives adequate sunlight or provide artificial lighting if necessary.
8. Monitor the moisture levels regularly and water the plants as needed, making sure not to overwater.
9. Observe the growth of the plants over time. As the roots grow, they will penetrate the transparent layer, allowing you to see their development.

Note: Transparent soil may not provide the same level of nutrients as traditional soil, so it's important to monitor the plants closely and adjust fertilization if necessary. Additionally, the silica gel or sand layer may not provide optimal aeration, so it's advisable to conduct this experiment with hardy plants that can tolerate these conditions.

Remember to research the specific needs of the plants you plan to grow and adjust the instructions accordingly.