Hey team,

Sorry to get back to you so late, I hope you see this! I really enjoyed working with all of you too. I'm really grateful you were all so engaged with your experiment and I hope you stay interested in plants. You all did a great job with this project. I hope the rest of the school year goes well and that you have awesome summers!

Hi Jack,

Those are great questions and there's no simple answer! Common fertilizers include the elements nitrogen, phosphorus, and potassium, which are required for plants to survive, but different plants need them in different proportions and at different stages of their growing cycles, so what you give a particular plant and when can vary a lot.

Amount of fertilizer relative to amount of soil, water, pot size, etc. definitely matters, and it’s pretty easy to over-fertilize some plants if you’re not careful. Fertilizers will usually have instructions for using the right proportions on the package. The location of the fertilizer also varies depending on the plant or type of soil you’re using. Lots of fertilizers come in little pellets, and those are usually either mixed into the soil before potting the plant or sprinkled on top of the soil, which results in small amounts of the fertilizer dissolving into the soil every time the plant is watered. There are also foliar (leaf) fertilizers you can spray onto plants, which is what I usually use for carnivorous plants (they are native to soil with very poor nutrition, so their leaves have evolved to absorb most of their nutrients rather than the roots, to the point that using fertilizer in the soil can actually be toxic to them). 

There should be lots of information online about which fertilizers to use on corn since it’s such a major crop plant. Testing the effects of fertilizer when growing corn in different soil types could be a cool experiment to follow up your current one if you have the time and resources to do that. Also, it looks like you’re starting a new experience with pot size. Can you tell me more about what you’re doing with that? Are you transplanting all of your current plants into larger pots? Are you still using vermiculite vs. potting soil in the new experiment?

Hello everyone! Thank you for the updates and I'm sorry to get back to you so late. That's awesome to hear your plants started growing so well. Just to make sure I understand, you're growing corn plants in vermiculite vs. regular potting soil, right? Are those the only differences (meaning, are you watering them all the same amount, giving them the same amount of light, etc.)? Also, what is the main thing you're trying to find out with this experiment (your "question")?

In terms of leaves dying in the vermiculite, I wonder if your plants in the vermiculite are not getting enough nutrients that your other plants are able to get from the soil. Which leaves seem to be dying? Is it mostly new leaves or old ones (or both)? Knowing that can help us figure out which nutrients the plant needs, which you might be able to supply with fertilizer. Even if you can't solve that issue, though, seeing that leaves tend to die when the plants are grown in vermiculite as opposed to soil is very good information! It sounds like you are getting some useful results from this experiment.

Feel free to post photos of your plants if you have them or ask any other questions you might have. I will be sure to respond quicker now!