Clay - Purchased earthboxes say that you can put two tomatoes per box. This is true, but since I am making them and they are much cheaper than buying them, I tend to only put one per box, and I also buy bigger containers than the earthboxes. I want to give my tomato roots *lots* of room to roam. I did experience much better yields from the homemade boxes that only had one plant per box. That being said, if it comes down to not planting a new variety and not putting a second plant in the box... I will put a second plant in the box.
creister- adding a cup of lime to the soil is recommended for tomatoes, since potting soil tends to be somewhat neutral in ph. Tomatoes like a higher PH, and like the calcium. As far as fertilzer goes... I put a strip of two cups of 10-10-10 fertilzer in a row, the furthest from where I place tomatoes.
However, I against all that the earthbox says I do add some "Miracle Grow, Blue stuff" to the water. I add two scoops once a week when the plants seem to stall in growth or flower production. I don't know why the folks at eBox say NOT to add "blue stuff", maybe it effects the wicking properities of the soil, but I have never seen any undue effect from it.
The biggest benefit I can see from using a homemade earthbox compared to any other container (or in ground plants for that matter) is this:
Consistant watering
The soil only wicks as much water as it needs.
The roots only take as much water as it wants.
The reservoir will supply both of these as long as it doesn't go dry.
And from what I have read about tomatoes, the biggest problems with tomatoes come from inconsistant watering.
Blossom End rot: Comes from extremes in soil moisture.. too moist or too dry - cause calcium deficiency.
Cracking: Too little water, followed by to much water.
Yellowing of leaves, wilting, root rot, blackening of leaves, fruit drop.. all caused by inconsistant watering.
A secondary benefit, is NO WEEDING!
Also if you find the area you picked gets not enough / too much sun, you can move the box.
And despite what some people say you don't need to grow dwarf varieties or determinates in a box. I grow only indeterminates (save for Silvery Fir Tree which I grow to get tomatoes before anyone else) and they all grow to a freakishly large size. These plants are 8 to 10 feet tall! Small children have gotten lost in them! There is a troop of boyscouts still missing in the Cherokee Purple! I can see their little camp fires now..
Okay, sorry I get carried away.
Selfwatering containers are a very sensible way to utilize space. Any questions?
