Stunted Growth in Mel's Square Foot Garden system

Asked July 3, 2013, 6:48 PM EDT

I am an Advanced Master Gardener and a Master Composter but you would never know it. My first 3 years with the Square Foot Garden system were great! This year plants have gotten stuck at 5-6". I added the usual annual compost (Mr. Earth this year) to Mel's recipe, supposedly to maintain the 1/3 compost, 1/3 vermiculite / 1/3 peat ingredients. I topped with home-made compost and home-made vermicompost. When I started to suspect trouble, I fertilized with Garden Tone once and with Fish emulsion with K weekly, 3-4 times. Where in past years we were bursting at the seems with beets, for example, this year we have many short plants with outer leaves that continually yellow and droop off. I live in Empire, MI. The box faces west looking out over Lake Michigan and is completely in the sun by late morning. The box has a bottom (sits on cider blocks) so the surrounding wild raspberries won't don't creep in. (Raspberries are kept several yards back beyond my wide border of straw.) So disappointing! Your thoughts? Is Mel's mix not one that lasts long? No indication of this in his Square Foot Gardening book. The photo attached is 2 - 3 years old. Thanks for your ideas !!

Leelanau County Michigan fruits and vegetables

3 Responses

I have absolutely no idea what Mel's mix is. But the part I am not hearing is about actual mineral soil in this box. Compost and vermiculite are great but where are the minerals? Mineral soil is going to give you calcium, magnesium, potassium, phosphorus and a ton of micronutrients that mixing your own organic matter does not.

For big companies thst produce soil-less potting medium products, they have chemists and soil scientists blending the stuff. It sounds like you nutrient balace is off. Or your pH could be off. Or both could be off.

Are these plants covered all year? This can really cut down on the amount of light the plants get.

Thanks for your time and thoughts Gretchen. Perhaps I can add more information that will clarify some of your questions and stimulate more thought and comments from you and others. If you google "Mel's Mix" you will be lead to much information about his mix and about his book that Master Gardeners are asked to read. Mel Barthalamew (spelling?) wrote his Square Food Gardening books / series for those living in countries with poor soil, little water etc..... and for other challenges as well, as explained in the book. (My challenge was the nearby wild raspberries shown in the I LOVE to experiment with gardening techniques.) Then, if you google the contents of "Horticultural Vermiculite" you will find that this 1/3 of his mix is where the minerals come from. Using the three ingredients listed in my initial posted question, as nurseries / growers do, allows one to grow without adding the diseases and seed bank from soils, without rotating crops, without watering as frequently, without weeding, without taking years to "condition" poor soil, without concern about pH... and on and on.

Regarding your row cover / light question, I use it in early spring 24/7 till flowers bloom so the bees can get in. And I use it in early summer at night if it's cold out. I used it much MORE during summer DAYS in former years when I was having great success. So I was actually wondering if I should go back to using it more again THIS year because perhaps my problem is related to the cool weather here this year? Although farmers here are complaining of a slow growth start to corn, I see only large healthy beets etc at farmers markets here (but perhaps they are grown in hoop houses?).

Unless I am missing something, Mel's book specifically says to add only compost annually. However I had a question mark in my mind about the vermiculite because it's no longer as course. I'm wondering if it is breaking down and minerals are no longer as plentiful therefore. In light of your response I will try to scratch in some new Horticultural Vermiculite around the plants and see what happens. Meanwhile I am very open to additional comments. I wish I could figure out how to contact Mel. Thanks!

I have been a Master Gardener instructor for over 25 years and have written several chapters in the book and I have never recommended Mel or his mix to anyone. I do not even know about this guy. The Master Gardener Program is not supposed to endorse anyone or anything or ask you to read books.

You next choice is to contact the MSU Soils Lab and find out what you need to do to get a greenhouse media test. This is the equalivent of a soil test but for artificial media. They will test it to see if it is balanced. If it turns out that there is nothing wrong with the mix, then look at light and other environmental issues. You can find them by searching on Michigan State University Soil and Plant Nutrient Lab. I am not in my office so I don't have the information here.

Beets are a cool season crop and if weather is cool, they should be thriving. I just don't think that vermiculite is a replacement for all the needed macro and micro minerals in soil. Good luck.