Saturday, August 22, 2015

HVAC Condenser Irrigation Experiment

Date: 7/25/2015

Week 0: I'm trying this experiment: I've just put some squash, gem and pumpkin seeds under a few inches of mulch and resting on the soil. I've taken a pool backwash hose (because I had some) and am redirecting the a/c condensation run-off to that patch.

Date: 8/2/2015

Week 1: Came back from vacation yesterday and noticed that 6 of the 10 seeds have germinated and pushed through the inches of mulch and are looking healthy. The trick (IMO) is to immediately go on a 1 week vacation after planting. The experiment is to keep the plants permanently wet/damp from the A/C drip pipe.
Some other notes about this: My wife planted the same seeds in a nearby vegetable patch 3 weeks ago and they are around the same size as mine are after a week. The key differences:
Hers: High quality soil, watered once a day for 10 minutes at 6am using city water, no mulch.
Mine: Placed on top of regular dirt (i.e. not "planted"), a few inches of mulch on top of it, permanently wet/damp with distilled water from a/c external drip pipe.

Date: 8/8/2015

Week 2: It's been 2 weeks since I "planted" the 10 seeds and here is the latest update.

Week 0: Planted

Week 1: 6 germinated, inches high.
Week 2: 7 germinated: 3/3 squash, 2/3 white pumpkin, 2/4 gem squash. At least doubled if not tripled in size since Week #1 update.

Other notes. On the other side of the house I have another a/c drip line. The water in that one I'm catching in a bucket. This means that I can measure the amount of water being produced by the a/c units and can assume that this one varies at the same rate. The amount of water coming out the unit on the other side is around 3 gallons a day right now but earlier in the week it was probably half of that. As you would expect the amount of water produced is directly related to the humidity and with this extra humidity over the last couple of days we have extra water. This is the inverse of what I think we need. i.e. when the air is dryer I'm guessing the plants will transpire more and need more water which is when the a/c run-off will produce less. Just thinking out aloud here...

 Date: 8/15/2015

Week 3: Looking healthy. Not showing any signs of over-watering yet that I can see.


 Date: 8/22/15

Week 4: Heat has been brutal over the last couple of weeks with highs of 115F and no rain for 2 weeks. Because the leaves are now so big the plants wither and droop during the afternoon. In the early morning they look the healthiest as in this photo.

They are now standing 12 inches from the soil. Because they're tangled together in a growing mass I haven't been able to work out if there are still 7 plants growing here.

Date 8/29/15 8am

Week 5: I now have a plastic garden chair that I keep to the south-west of these plants. This provides some shade during the afternoons. Because of the size of the leaves there is severe wilting in the afternoon. In the evenings and mornings the leaves have fully recovered. The afternoon wilting is not because of a lack of water but rather the ability for the plants to pull the water up through their stems during the hot periods of extreme transpiration.

Today I measured the plants. I should have started doing this earlier in the experiment to measure growth rate. Height (off mulch) is 12 inches and average diameter is 20 inches. I also added the time of day to the sub-heading. Because of the wilting it's important to take the measurements at around the same time of day and preferably in the morning.

Date 8/29/15 2:30pm

Here's another photo of the plants taken 6.5 hours after the one above. The temperature has risen from around 85F (29C) at 8am in the morning to 110F (43C) at 2:30pm. Those wilted leaves will recover this evening.

Date 9/14/15

Week 7. Not looking that healthy right now. I've been away for the last week so not sure if it's the sun or over-watering. It rained overnight. Plants have started to crawl horizontally now.

Date 9/19/15

Week 8. Very little progress. Still looking heat-stressed. The extreme heats have started to abate. Highs are now under 100F. In theory they should be getting less water as the A/C units should be running less with the drop in temperatures.

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