To store hydroponic nutrient solutions right, keep Part A and Part B in separate opaque containers. Never mix them until you are ready to use them. Mixed solutions go bad faster than sealed concentrates do.
I ruined a batch of nutrients by storing them in clear jars on a sunny windowsill. Within two weeks, green algae grew inside and a white crust formed on the bottom. The solution turned murky and smelled off. I had to throw it all out.
Light causes two problems for your stored nutrients. First, it fuels algae growth that uses up nitrogen and other elements. Second, it breaks down chelated iron and other sensitive compounds. Opaque containers block this damage from happening.
Nutrient concentrate storage needs the right temperature too. Heat speeds up chemical reactions that degrade your mix. Cold can cause some compounds to drop out of solution. Keep your bottles between 50-80°F (10-27°C) for best results.
Nutrient solution shelf life varies by storage type. Sealed concentrates last 6-12 months when stored right. Once you mix your working solution, you have only 7-14 days before it starts to break down and lose strength.
Your hydroponic fertilizer storage area should be cool, dark, and dry. A basement shelf or closet works great for most growers. Avoid garages that get hot in summer or freeze in winter. Swings hurt more than steady temps.
Glass bottles work well for long term storage if you can find dark colored ones. Plastic food grade containers in opaque colors also do the job. Never use metal since nutrients can react with it and become toxic to plants.
I label all my containers with the mix date and contents. After a few months you forget what is in each bottle. Good labels save you from mixing the wrong things or using nutrients that sat too long on your shelf.
You can tell your nutrients have gone bad by a few warning signs. Cloudiness that was not there before means precipitation. A foul smell suggests bacteria grew inside. Crystals on the bottom show that compounds have fallen out. Toss any batch that shows these signs.
Some growers try to save money by mixing huge batches of working solution at once. This rarely works out well. You end up with weak or degraded nutrients by the time you use the last of it. Mix only what you need for one week.
Keep your reservoir fresh by doing complete changes every 7-14 days instead of just topping up. Old solution builds up waste products and loses balance over time. Fresh mixes give your plants the best nutrition possible.
When I first started growing, I bought a year supply of nutrients to save on shipping. Half of it went bad before I could use it. Now I buy 3-4 month supplies at most and store them in a dark basement closet.
When I travel, I ask a friend to check my systems but not add nutrients. A couple days of plain water causes less harm than nutrients mixed wrong. My plants always bounce back once I return and mix a fresh batch.
Read the full article: Hydroponic Nutrient Solutions: The Complete Guide
