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Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by danhardman on Tuesday June 27, 2017 @08:38AM (#14644798)
Did the pot you use have holes in the bottom? It looks like you have it just sat on a desk so I'm assuming it's basically just a bucket?

Your moisture problem could just be that you were relying too much on the water evaporating/being absorbed rather than needing to drain out. Gravel at the bottom of a pot with holes in helps water drain really well. Alternatively, without the gravel you could place the pot on a dish, fill the dish and let the water be absorbed from the bottom up.

Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by reitanqild on Tuesday June 27, 2017 @11:26AM (#14646238)
Agree.

Alittle more details about watering:

IIRC many plants grows best in the long run if watered thoroughly and then left to dry up a bit in between.

The reason for the drying is the drying causes the roots to grow. And the reason for why it should be really soaked when watered is so that the roots will stretch towards the bottom instead of spreading out on top.

(Correct me if I'm wrong, I left farming school almost half my life ago && English is not my mother tongue.)

Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by mtlynch on Tuesday June 27, 2017 @08:41AM (#14644819)
Yeah, it drains into a little tray underneath. I'm trying to figure out a better solution for that because we can't see how much water is in the tray, so if too much has drained out, it starts overflowing onto the table with no warning.

Also I get the sense that I shouldn't just be leaving standing water in the tray forever, but it's also pretty difficult to remove the tray and empty it.

Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by hammock on Tuesday June 27, 2017 @09:47AM (#14645315)
Put some pebbles on top of the tray to raise the pot off of it, so it's not sitting in the standing water.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by mtlynch on Tuesday June 27, 2017 @10:07AM (#14645476)
Oh that's a good idea. Thanks!
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by and0 on Tuesday June 27, 2017 @10:51AM (#14645899)
I usually throw a base of pebbles / marbles into the bottom of any pot before I put the dirt in, which also aids in draining.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by Ham5ter on Tuesday June 27, 2017 @11:11AM (#14646096)
Why not connect your tray, back into the Watter reservoir?

This way, it cannot get to Wet, and you could just Pump that Pot full with watter, any excess watter, will just drain through the Soil back into the reservoir :)

Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by ZirconCode on Tuesday June 27, 2017 @12:11PM (#14646696)
Dirty water in the pump is bad.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by andegre on Tuesday June 27, 2017 @10:11AM (#14645517)
Put another sensor in your tray wired up to your UI, so as soon as the sensor goes from 0% to 100% for moisture, you know to empty your tray.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by mholmes680 on Tuesday June 27, 2017 @10:39AM (#14645771)
what if the tray was the way to detect moisture level? or, you could drip it back into the supply water?
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by kingosticks on Tuesday June 27, 2017 @08:47AM (#14644852)
If you are growing from seed, does the bottom up absorption still work or do you need roots first? I tried googling this but I'm reluctant to visit some of the "green" websites that dominate the results from my work computer.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by roel_v on Tuesday June 27, 2017 @10:22AM (#14645618)
You'll probably want to germinate in small containers, which work fine when bottom fed. I use styrofoam cups that are placed on top of a capillary mat, which draws water from a container underneath. Works great, keepz the soil moist but not wet. I have these in my indoor seed starter; it has temperature controls and fans to keep young plants moving. Works great for mint, tomatoes and peppers. Peppers actually like to be 'abused' a bit - periods of drought, hard winds, large variation in temperature. Makes them very bushy with thick stems. With a computerized system this is easy to implement, but the problem is how to measure the response variable in such a system (or even define it) to set up a fully self-regulating system. The hard- and software in these systems are easy, it's the botany, biochemistry and horticulture that is hard.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by Thews on Tuesday June 27, 2017 @09:02AM (#14644948)
Lots of plants like to be top fed. Also roots of different plants can grow differently for aeration. Probably best to educate yourself on horticulture more so than software and sensors.
Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by adrianN on Tuesday June 27, 2017 @08:49AM (#14644870)
It depends on how deep your pot is. For normal pots it probably doesn't work without roots.