I am thinking about making myself an office table. I want to put a plexiglass top on the table and then put small plants under it. My concerns are the water hazard and insects. Can we use something except soil to grow the plants?
Regarding the polyacrylate crystals, you will probably need to support the plant because the crystals are a loose substrate and polyacrylate expands and contracts with water amount, which causes upheaval, and essentially can cause the plant to fall over.
If you can't find agrosoke crystals or polyacrylate in your area, you can rip open a (clean) diaper to get the crytals. The crystals typically expand about 20 fold. Or, search online for plant gel... chances are you will find both products for sale (plant agar and polyacrylate).
Sure, look at hydroponics for different types of media which can include:
- glass beads
- baked clay beads
- crushed volcanic lava
- no media at all - just suspend the plant over a nutrient solution (aeroponics)
- coconut coir or husk
- soilless mix for interior plants which has peat, perlite, vermiculite
You will have to be careful about leakage no water what you do. Some plants grow better in some mediums than others. For low light houseplants in a glass table I would choose coconut husk.
If you choose something other than soil you will have to compensate by providing nitrogen, phosphorous and potassium as well as trace nutrients. Seeing as this is for an office it will be low light and you should be able to get by with fertilising two or three times a year.
You can actually use soil, but you have to make sure it's free of pests and their eggs:
I take a big aluminum roasting pan, add soil and or potting soil and or compost, and then some water. I cover it tightly with aluminum foil, put it on my gas grill, run my gas grill with the burners on medium for a couple hours. The soil is well-cooked and pest free. The water and sealing it keeps it from baking into a solid rock. Before putting it into my indoor plant pots, I also mix in perlite.
I do it this way because there's organic matter in the soil, and it creates a pretty strong smell if you cook soil in your oven, though you can do it that way, too. If you Google "baking" or "sterilizing" and "soil" you can probably get more accurate information on time and temperature.