Question
QUESTION: Hi Elyse

I've been hearing wonderful things about a self-watering pot and how they can help regulate watering uptake.  however, I have some questions!  I am planting tomatoes.

1. What happens if the tomato (or any plant really) is newly transplanted, or doesn't have roots long / deep enough to get to the reservoir? Do you keep watering from the top?

2. What's the best way to get water into the reservoir (whether plant is big enough or not) - would you keep filling it up by watering the tomato from the top?

3. If the roots can't reach the reservoir and I've been watering from the top, will the water in the reservoir just sit there, and can disease arise as a result?

4. Once the reservoir water IS being used, does that mean you completely stop watering from the top, and let the plant draw water only as it needs?  Won't that make the top soil quite dry?

5.  Would you recommend self-watering pots in the first place?

Thank you

ANSWER: Dom:
The plant roots get their water from the soil. The soil takes up water from the reservoir. You water from the bottom at all times. Self-watering pots can be a time-saver and assure constant watering, as long as you check the reservoir level and do not let IT go dry. The downside is their cost - do you need them? If you are not home during the day and your pots tend to dry out, or you are not good at remembering to water (I know someone like that!!), then they may be a good thing for you, especially for tomatoes.

Elyse

---------- FOLLOW-UP ----------

QUESTION: Hi Elyse

I just never seem to know when my plants are watered deeply enough - I've pulled out old plants from the previous summer from a container, only to realise the roots down go down very deep at all.

However, I'm still confused about how they work - how will the soil take up water from the reservoir all on their own?  I had thought the roots would stretch down when needed and take up water, but that doesn't explain how they'll do it if the plant is newly transplanted and the roots haven't gone deep enough yet.

ANSWER: The best way to understand it is probably with a demonstration. If you have a small pot, like the plastic ones your starts come in, fill it with some potting soil and tamp it down well. Then set it in a shallow container of water - about 1" should do it. Leave it there for a few hours, or overnight. Look at it the next day, the water in the reservoir should be gone, and the surface wet. If one and not the other, then there was simply not enough/too much water in the container.

I didn't understand your first sentence - I think you meant to say that the roots hadn't grown very far down in the pot? If you are speaking of tomatoes, then I would say that they were never given enough water. Roots grow towards water. If you put a plant in a 12" deep pot and water it well, roots will grow 12" long. If the water only reaches 8" down, that is as long as the roots will get. If they are in a 18" deep pot with plenty of water, they will grow 18" long. Understand?

By the way, tomatoes should be in at least a 3 gallon pot for a good sized plant for best production. You can grow them in smaller pots, but you wont' get as good a yield.

Elyse

---------- FOLLOW-UP ----------

QUESTION: Oh, I apologise - yes that's what I meant with my first sentence - presumably, the shallow roots meant that I hadn't watered deep enough in the first place, and you confirmed it.  That is why I think I could use a SW pot.

Alright, here is my inability to understand in basic - I understand how your example would work because the pot and water are in direct contact.  However, there is that 'barrier' in a SW pot, with only little holes soil can take water from.  After a while, the reservoir will get low, and the soil+water is no longer in direct contact.  How then, will the soil continue drawing from the lowered water reservoir?

(I may be missing a gene that enables people to udnerstand basic concepts and science).

Answer
OK, now I see your confusion. I don't know exactly what you mean by a barrier, but there are many self-watering pots and they have different designs. Many of them have a wick that  brings the water from the reservoir to the soil, so it wouldn't matter how low it was, as long as there was still water in it. (though they work better with more water)

If that is not the case in the ones you are looking at, there is probably some kind of level indicator, and the reservoir needs to be kept at or above that level for the soil to take up the water. None of these pots are a one-time fill type thing, they still need tending, just not as often. How often will depend on a number of factors - size, soil mix, temperatures, etc. You might want to look at a number of pots and choose the design that will work best for you and your lifestyle.

Elyse

PS. I'm signing off now, so if you have further follow-up I won't get to it until tomorrow morning.