Week 12: 20 Feb – 26 Feb

Sunday 20th February: I managed to purchase a couple of new grow lights (200 w (6400k) white/blue spectrum) from a local horticulture specialist and installed the new lights in the installation. They seem brighter and I decided to extend the light hours to 14 hours a day (6 am – 8 pm). I will check tomorrow to see if the 14 hours with new lights is over doing it for the trees.

No change to the welfare of the trees although the yellowing on the leaves seems to be slowing down. Whilst installing the lights I took the opportunity to remove any yellow leaves that were ready to fall. I have learnt that if you gentle pull your hand over the branch the leaves that are about to drop will come away. In this manner the branch is left unaffected. I have also observed that the skeleton branch will change colour and, eventually, the tree will drop the branch. All of this is part of the growth of the trees as they select their energy use to survive.

The temperature within the propagator had remained steady at 27 degrees Celsius (80.6 degrees Fahrenheit at soil surface height. The humidity had dropped to 41%. I want the humidity to be within 10% either side of 50%. So 41% is alright but could do with being slightly higher. By careful control of the vents I am beginning to get better at controlling the humidity levels and, consequently, the heat within the installation.


Monday 21st February: The current duration of lighting doesn’t seem to have adversely affected the trees. The trees still seem unwell and more leaves had yellowed overnight. The humidity has dropped to 36%; below the minimum best of 40%. I opened the environment and took a long and close look at the trees. The soil deep in the pot does still feels cold and wet. I aerated the soil of each tree. The soil needs to dry out more and so I hope a combination of aerating plus an increase in temperature of the environment will quicken the process.

I replaced the trees back into their cased environment and increased the temperature of the reader that is positioned at soil level. I set this at 28 degree Celsius (82.4 degrees Fahrenheit). This means that the base temperature is 31 degrees Celsius (87.8 degrees Fahrenheit). Whilst these new temperatures altered the environmental conditions I also closed the vents with the exception of the top ones. The humidity rose to 46% and seemed to stabilise at that level.

It is dispiriting to arrive at the installation hoping that the attention from the day before would have encouraged better health in the trees only to find little improvement or worse. That said, I will be back tomorrow to check again on the environment. This is the labour of the project and I am learning much from these closely observed changes within the immediate environment of the trees; a labour extricated from capital; a labour valued through the co-relationship of the trees and me as a study within a study.


Tuesday 22nd February: This morning the environment had not changed from the settings of yesterday and the trees seemed to have stopped yellowing and dropping their leaves. The humidity was at 46% and the temperature at top soil level was 27.7 degrees Celsius (81.86 degrees Fahrenheit). This is the first day for 13 days where I have not had to make any changes. I am aware that the humidity could be a bit higher and do expect the level of humidity to drop as the soil dries. If the level drops below 36% I will introduce a couple of small bowls of water into the environment. Humidity is important to the welfare of the trees as the clusters of water molecules in the air can restrict the photosynthesis of the trees. At very high levels, (85-95%) humidity, the water vapour density does affect the transpiration of the tress.  Plants breathe through tiny openings on the undersides of their leaves called stomata. The leaves open and close their stomata under certain conditions. If the temperature becomes excessive and causes a tree to start loosing more water than it can take up the tree will close the stomata’s on their leaves in order to slow down the water loss; all of which means very high or low humidity is not good for the trees. For now I am happy to let the environment stay in its current settings and balance.

Looking back I am pretty sure that the combination of watering the manure and a temporary break down of the heating system meant the tree’s environment became a winter one. In such conditions the trees would do everything to survive. In this instance the trees would drop their leaves and conserve energy.


Wednesday 23rd February: The environment seems to be raining stable with humidity at 46% and the temperature at top soil level was 27.7 degrees Celsius (81.86 degrees Fahrenheit). I opened the propagator in order to remove some leaves that had fallen and to check the moisture of the soil. It has been a week since the trees were watered with approximately 8 fluid ounces per tree. Despite the top soil looking very dry the soil about 3 inches (7.5 cm) down is still fairly moist. I have decided not to water them until I am sure the trees need it. Moringa Oleifera trees are drought resistant. This is because the trees have a tap root that will go deep into the earth to find water. However when the trees are grown in pots the tap root is limited by the height of the pot. This one of the reason why it is recommended to plant the trees into large pots when the tree is between 60 -80 cm in height (approximately 12 -15 weeks). If possible, this should be the final re-potting as Moringa Oleifera trees do not like being re-potted.

Another reason to pot the young trees in large pots is that it is thought that they, like some other plants and trees, have the capacity to calculate the volume of soil it is in. These trees and plants will then grow only to the capacity that the sense the volume of soil will sustain. If this is correct then a tree in a small pot will stop growing as it reaches its calculated limit.

The tallest trees are now within a few inches of the top of the propagator. Ideally it is best to keep a distance of approximately 7-9 inches (18 – 23 cm) between the tops of the trees and the lights. If the lights are too distant then the plants and trees can suffer from ‘plant stretch’ as they pull towards the light. Plant stretch will produce thin stems and can cause the trees to fall over if the problem is not corrected. That said, even with a new height extension the lights will be approximately 9 – 13 inches (23 – 33 cm) from the tops of the tallest trees. I think this is a reasonable distance. I may install the new extension at the beginning of the next.


Friday 25th February: I was away yesterday on a project site visit so I was anxious to visit the trees.

The environment was much colder than it should have been; registering a temperature of 23 degrees Celsius (73.4 degrees Fahrenheit) at top soil level. This is some 8 degrees below what it should be. The humidity was also at 65%. Clearly the lower temperature had increased the humidity. There was some yellowing of the leaves but less that on prior visits. I checked the installation and realised that the temperature sensor had dropped from the top of the pot, resting on the top soil, to the base of the structure. This will have lowered the temperature considerably. I can only speculate that someone had pulled at the wire of the temperature sensor or had banged into the structure causing the sensor to drop. The more likely of these options is pulling the wire. This is half term week and a child could easily have played with the wire. These moments or incidents are all part of the ontology of project; an evolving material history.

All in all I know I have probably caught the problem in time and would never wish for children not to visit art galleries. My childhood was spent in many happy hours walking around Birmingham City Art gallery while my mother and sisters went shopping. I can’t honestly say I didn’t fiddle and play with some of art I came across. To prevent the problem happing again I tapped the wire and sensor into position.

The plan had been to water the trees today. It has now been 9 days since they were last watered. Having opened the structure I checked the soil of one of the trees. The soil was still fairly moist. It was also pretty cold due to the temperature drop. I decided not to water them but did give the top soil a light misting on each of the eight trees. I think this was sufficient to slightly soften the surface of the soil which is predominantly made up of quite dry manure.

I reset the temperature sensors and closed the environment opening only the top two vents on either side. I sat with the installation for about and hour and checked that the installation was warming up. As the heat rose the humidity started to fall. I returned several hours later and was pleased to see that the installation had returned to its set conditions. The humidity was at 51%. The temperature at base level was the temperature at top soil level was 27.7 degrees Celsius (81.86 degrees Fahrenheit).


Saturday 26th February: The trees have deteriorated overnight with many yellowing and fallen leaves. This is difficult as I think I have tried most variants and possibilities. I went for a coffee and a think.

I decided to link the heater into the light cycle. I am now running them off the one timer. Up to now the heater has been on almost continuously and I am wondering if the trees need some element of cold overnight. This will change the environment and I predict much greater fluctuations in temperature and humidity but it will be more accurate a replication of the rhythm of a natural climate. I am also very unsure about watering. I did check yesterday and they still seemed moist but it is now 10 days since they were last watered. Tomorrow I will check how the environment has responded to these changed conditions. It is amazing how even a fraction of a degree in temperature change can alter the complexities and effects of our environment. The installation will experience a change of approximately 10 degrees over 10 hours; a cooling and heating that attempts to better replicate a natural cycle and maybe help the trees grow stronger.

Approximately 1 cm (0.39 inch) of growth during this week

The tallest tree is now 54 cm (21.25 inches).


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