Can you explain "silica"?
Isn't that just sand? Silicon Dioxide.
What is your silica source? Diatomaceous earth?
Can I go to a beach on Lake Ontario and get a few buckets of sand?
Hey. So silica is one of the earth's most common materials. It's in alot of different things. The real question is.... Is it available for a plant to uptake ..?
Most forms of silica, (anything silicate) will need bacteria and enzymes to slowly break it down to become available to plants. This process is slow, and long and could take years to fully break down even with some materials. Personally I use mono silicic acid which is bio available, and slower releasing silica sources in the soil itself like diatomaceous earth, quartz, sand, oyster shell flour.
So yes...answer to your question. I mean yes you COULD do that. But I'm sure your soil contains some sand in it anyways and the amount of time it would take to break that down into bioavailability would probably be past your expiration date anyways. Better to use something that breaks down faster or is already bioavailable. Potassium silicate is a silicate and needs months before it's broken down into an available form. Most people see benefits from the small amounts of boron and manganese companies add into most silicate blends like stronger stems rigid leaves and assume it's the silica doing it's thing when in fact it's not.
Take some time and read into it. You'll see most products are just 'snake oil'. Expensive water with some stuff that won't benefit you anyways. In the garden it's a bit different as you aren't changing the soil like is common with indoor cannabis cultivation.... The silicates are left to break down over time and can benefit your garden for years.