Plant FAQs

Is it safe to eat what I grow?

Remember, anything you add to your Garden will ultimately end up in the plants you eat! In general, this is not only perfectly safe, it’s a great way to grow clean, healthy food, but we recommend using fish food that’s intended for aquaculture or aquaponic use, since pet store formulas may contain dyes or preservatives. If you do buy food from a pet store, choose a premium brand with as few additives as possible. You can add whatever you like to your Garden, but we suggest not putting anything into the water that you wouldn’t feel safe putting on your dinner plate!

Do I need to add fertilizer or supplements to my plants?

Quality fish food should provide the majority of what your plants will need to grow; keeping the pH of your water in an appropriate range (6.4-7.0) will help make sure your plants are able to absorb these nutrients well. However, every now and again you may find it helpful to supplement certain minerals, especially for some plants with unusual needs. 

  • Potassium: Symptoms of potassium deficiency can include purple spots on the underside of leaves, curling leaf tips, brown scorching, or yellowing leaf margins. Potassium carbonate is an excellent tool; it adds potassium for your plants, and it’s also alkaline, so it’s useful for raising pH, which you’ll likely occasionally need to do anyway! Add it when your pH is too low and you’ll probably never need to supplement potassium otherwise. You can also use potassium chloride if you need potassium without raising pH.
  • Iron: Your garden might have an iron deficiency if your plants start turning yellow while the veins remain green. Iron can also frequently help boost production even in plants that aren’t obviously deficient. You can boost the iron levels in your garden by adding a chelated iron supplement. 
  • Calcium: Calcium is important for growth in the plant’s cell walls; calcium deficiency often appears as twisted, stunted, or “rippled” growth in the small, young leaves of plants. It can be tricky to add calcium without raising pH excessively, since most common mineral sources are alkaline. One of the best ways to manage calcium is to add a solid calcium mineral like limestone or even pieces of eggshell, since it will dissolve slowly rather than causing pH to suddenly spike upward.

When starting a new aquaponic system, some growers will use a natural mineral fertilizer to preemptively provide trace minerals for their plants. These come in powdered and liquid forms, and may be derived from a variety of sources, although seaweed extracts are most common.