Oh. My. Goodness. My brain is full to bursting with new gardening knowledge from my Extension Master Gardener Core Course (which I wrote about here). Approximately 75 hours of in-person classes over 8 days, 409 pages of reading, 14 online quizzes (I passed!) and dozens of pages of handwritten notes I may or may not be able to read again. I have a whole list of things I’m inspired to do differently this year – new annuals to try, new mulching techniques, better composting practices, and maybe finally getting a raspberry patch going. And oh, yes – I will be getting a soil test this year. I promise. We haven’t tested it in 8 years, and we’ve done a lot of amending since then. The only people who harp on the importance soil testing more than the good folks at Garden Maker are the educators at the Master Gardener course!

Anyway, I thought it would be fun to share the most interesting and noteworthy things I learned in my class:

  • In Minnesota, we have “young soil” because of the glaciers that covered our area, which means it has higher relative fertility than older soils that have been cultivated longer in other areas.
  • Black walnut trees are allelopathic, meaning they produce a biochemical that prevents many other plants from growing nearby. So if you have a black walnut tree, don’t put any of the leaves or branches in your compost!
  • Calcium, which is important for tomatoes, is usually abundant in soil. However, it can only be taken in by actively growing roots, so if we disrupt the roots with tilling, we’re hurting the calcium uptake (which could be one of the problems with our tomatoes!).
  • That nasty blight we keep getting on our tomatoes? It’s called early blight, it’s caused by the fungus Alternaria solani, and the copper we sprayed on our plants last year could have been effective at controlling it… if we had applied it earlier (right after blooming, or at the first signs of the disease). HOWEVER, copper is also a heavy metal, and therefore pretty toxic, and we probably want to try something different this year. 
  • In Minnesota, it is illegal to put phosphorus fertilizer on your established lawn unless you have the soil test results to prove that you need it. Phosphorus runoff from lawn overfertilization has been getting into many of our 10,000 lakes causing excessive algae bloom.
  • The saddest thing I learned in class is that there aren’t really any scientifically proven post-emergent organic herbicides. And so, I shall continue “mechanical means” of weed control – hoeing and hand-pulling. I did get good confirmation that our practice of using corn gluten meal as a preemergent herbicide & nitrogen fertilizer is indeed backed up by research.
  • Our most pesky weeds are Stinging Nettle (aka stingweed), Quackgrass, Smartweed, Quickweed (Galinsoga parviflora, aka the bane of my gardening existence) and Foxtail.
  • I now know what’s growing in our landscaping, which was planted when I was busy caring for an infant and a toddler. Those purple flowers our girls love so much are Echinacea.
  • Finally, I learned what a treasure trove of information there is on the Extension website for the University of Minnesota website. Be sure to check out the Extension website for your state, or a neighboring state, for some fantastic resources for growing gardens in your area!