ProMix BX vs 5:1:1 experiment

15 years ago

I had some extra tomato plants so I conducted a little experiment. I had two identical Better Boy tomato plants that had been started in ProMix BX on March 10th from seed in 4" pots. On April 5th (26 days) they were transplanted into 1 gallon containers. One container was filled with ProMix BX, and the other with 5 parts pine bark mulch (Greensmix brand from Lowes), 1 part perlite, 1 part peat moss. They were both watered with 1/2 tsp Miracle Gro 24-8-16 per gallon of water at every watering. . I inspected the plants on April 17th (12 days in 1 gallon containers, 38 days total). The results?

The ProMix BX showed a decent amount more top growth than the 5:1:1 mix, although they were both just starting bud developement. When I examined the root system, the 5:1:1 showed a larger root system with larger roots.

I performed the same experiment with Early Girl Bush, and Jet Star with the same results. Less top growth and a larger root system with the 5:1:1 mix. Here are some images of the Better Boy.

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ProMix BX left, 5:1:1 mix right

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ProMix BX right, 5:1:1 mix left

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ProMix BX right, 5:1:1 mix left

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ProMix BX right, 5:1:1 mix left

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ProMix BX right, 5:1:1 mix left

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ProMix BX right, 5:1:1 mix left

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ProMix BX right, 5:1:1 mix left

Featured Answer

tapla (mid-Michigan, USDA z5b-6a)

15 years ago

I didn't ask about the lime out of curiosity about pH issues, AK. I'm not surprised that the top showed a little more growth in the ProMix after learning there is no source of either Ca or Mg when using MG fertilizer in a soil that wasn't limed. It is surprising though, that the root mass of the plants in the 5:1:1 mix was greater than those in the ProMix. even in spite of the fact that the only source of either Ca or Mg was the medium components, which we would consider to me nil, practically speaking.

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Comments (9)

yellowthumb
15 years ago
Thanks for showing, excellent experiments.

I would go with the larger roots. Larger and whiter roots are healthier, means a bigger yield down the road.
meyermike_1micha
15 years ago
You know how I interpet that?

By the time the roots get big enough to support life above ground, the soil from anything less than the 5.1.1 will have collasped and suffocated anything that might of exsisted before this. Sort of what has happened to all my previous past life plants....

Mike..:-0)
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greenman28 NorCal 7b/8a
15 years ago
"As above, so below..."

A healthy root-system will support a healthier plant ultimately.

Josh
tapla (mid-Michigan, USDA z5b-6a)
15 years ago
Tsk tsk - you guys are probably on the very verge of being raked again for more of that didactic soil talk, so tread carefully. ;o)

Al
calistoga_al ca 15 usda 9
15 years ago
I am curious that I see no mention of added lime. Al
tapla (mid-Michigan, USDA z5b-6a)
15 years ago
I had wondered the same, but assumed he would have added it ...... but perhaps not. What say you, AKGM?

Al
akgardenman
Original Author
15 years ago
Long story short, no lime. I've always used ProMix but decided to try something else after doing some reading on this forum. My old trusty PH meter failed last month so I was unable to check this mix, but based on the lime question I'm guessing it's on the acidic side? My new meter should be here today so I'll check it.

I'm thinking because I used a bark "mulch" I should have eliminated the peat moss. The water retention was higher than I would have expected. Thoughts?
emgardener
15 years ago
Nice pictures. Thanks for posting.