Maple seedlings and soil mediums. Year two.

Summery

My tests indicate that mixed soils lead to the highest amount of growth. Sand seems to be an important factor. The substrates are scored on plant growth and plant survival. 2 means roughly that the plant provides both a favorable growth medium and the plants survive well in the medium. Akedama: 0, Bonsai Mix: 2, Chicken Grit: 1, Pine Bark: 1, Potting Soil: 2, Lava Pebles: 1, Sand: 2, Woodchips: 1, Zeolite: 0. It seems that "super rock" soils score 0, airated soils score 1 but mixed soils score 2. Further, certain results of this test lead me to believe that different soils may be better or worse for some plants depending on the desired result such as branch ramification (seems related to high nutrient soil), root growth (related to airated soil), height growth (mixed soil), girth growth (airatied soils), or slowed growth (acidic, or clay soil).

Stock

All 54 seedlings were sown at the same time from the same parent. They were of the same lot the maples from my first test. These were one year old and were chosen because they had lived in shade in the back of the grow area. The plants were 1.5cm to 2.5cm when planted. They were transplanted in January. The maples were planted 3 plants to an 11cm pot (4inch pot). The plants, 18 pots, were placed in 2 standard plant trays. The plants were outdoors in morning and afternoon sun. The plants were watered as needed, but watered sensibly as a group and not according to individual needs. The plants were all fertilized at the same time and rate with a water soluble all purpose 10-10-10 fertilizer applied at 1/2 strength every two weeks. 4 times throughout the spring and 2 times in the summer the 11cm pots were moved throughout the plant trays. By moving the plants to different positions within the trays I reduced the chances of a few plants capitalizing on great light conditions while others would suffer from less-then-perfect light conditions.

Substrate/plant observations

Akadema. Survival - 3/6. Heights in cm: 5.6, 5.3, 4.7

Akadema is volcanic clay from Japan. The plants from Japan grow in it naturally. It changes color when wet. It also grows a layer of moss in about a month, if you let it. Strangely, akadama gravel expands as it freezes. This can cause chaos to a plant planted in the akadama. The plant is lifted by the swelling, wich has no place to go but to the top of the pant pot. The plant is then deposited on top of the soil as the soil reduces in mass, but the plant is not pulled down - rather the soil settles down around it. Live mapes in akadama seem very healthy as indicated by their deep red summer color and leaf longevity. One plant in the Akadama still has a leaf in January. I suggest akadama is a good choice to add to a soil mixture for japanese maples.

Bonsai Mix. Survival 6/6. Heights in cm: 51.6, 37.4, 28.3, 26.3, 23.1, 6.9

This is a 1 part each of Chicken Grit, Sand, Pine Bark, and Lava Rock. It is screened under 1cm but over 2mm. This mixture was developed for bonsai in a rainy and wet winter environment. It is a favorate for conifers. This is probably the best mixture in this test.

Chicken Grit. Survival - 6/6. Heights in cm: 19.9, 14.8, 11.7, 6.6, 5.5, 5.0

Last year all the plants in chicken grit died in the very beginning of the test. Who knew that it could stand up on its own?

Pine Bark. Survival - 6/6. Heights in cm: 29.9, 21.5, 13.9, 13.3, 11.0, 9.3

Pine bark is very acidic. It is likely these plants had difficulty getting nutrients.

Potting soil. Survival - 3/6. Heights in cm: 69.5, 48.4, 41.2

This is a mix of 1 part each sand, peat and compost. It is from a bag marked "potting soil." The penjing clubs of Vancouver use potting soil mixed with gravels/sands/lava rocks, etc to increase drainage. The potting soil grew the largest 3 plants, but keep in mind that the 69.5cm plant was the only maple in the entire experiment that had a whole pot to itself. However, given the opportunity the potting soil/japanese maple combination proved awesome. I modified soil's score from 1 - poor survival but good growth. to 2 - for poor survival but amazing growth. The 69.5cm maple still has a leaf on it in January, too.

Lava Pebbles. Survival - 5/6. Heights in cm: 26.1, 25.4, 17.1, 15.4, 12.9

Lava pebbles were my favorate last year! I have so much planted in pure lava. Well, it does not provide top growth, but rest asured the awesome airation capabilities of lava provide a healthy root system. Also, the plants in lava rock exhibit some, but to a lesser extent, of akadama's heathy maple syndrome. That is where your maples are so thathy they are deep rich colors and they have leaf longevity in the winter. Two of the maples still have a leaf in January.

Sand. Survival - 6/6. Heights in cm: 40.3, 32.4, 30.3, 27.4, 22.9, 11.0

Oddly, sand is in the top three growth mediums. More oddly, sand is a major component of the other two growth mediums. Go sand!

Woodchips. Survival - 6/6. Heights in cm: 7.7, 6.8, 6.5, 5.6, 5.0, 3.0

It is said that as woodchips break down they deplete the soil of nitrogen, so those things growing in them cannot grow. Let me tell you, the nitrogen depletion makes my 10-10-10 into 9-10-10.

Zeolite. Survival - 3/6. Heights in cm: 23.0, 5.7, 4.6

Zeolite is a type of rock that holds water and nutrients in such a way that the plant seldom lacks either between waterings. Meh. Doesn't seem so hot to me. Maybe in small doses.