You can certainly use turface instead of perlite for more water retention, but I think the primary problem is your use of 5 gallon containers for tomatos in a hot, arid climate.

Even in my Wisconsin climate I tell people 5 gallons is the minimum size I would recommend. I can't imagine using a size that small anywhere warmer/dryer unless you don't mind watering multiple times per day or go semi hydro.

Your post reminded me that I forgot to mention that I've found some large tubs at the local dollar store for a song. They hold 18 liquid gallons, are about 2 inches taller than a five gallon bucket, and as big around as a thirty two gallon trash can. The diameter tapers down a bit from the top to the bottom but not a whole lot ~15 degrees.

I figured the increased soil volume would let the tomato plants stretch out more and increase the total water capacity. Also, this next season, I will be putting up a shade structure with 40% Aluminet shade cloth to reduce the scorching heat and blistering sun starting early summer. Maybe I can stretch out the prime growing season a bit longer. =)

Just so I understand: Turface provides all the benefits of pelite (faster drainage, aeration, etc...) along with an increased CEC and water holding capacity? Regarding Turface, how hard does it hold onto the water it absorbs? I've read that plants like a soil water suction of 30kPa to 200kPa and that some soils, like clay, can hold onto the water so tightly that the plants can't extract it. Is this hogwash or sound science?

Just so I understand: Turface provides all the benefits of pelite (faster drainage, aeration, etc...) along with an increased CEC and water holding capacity?

Correct. Regarding Turface, how hard does it hold onto the water it absorbs? I've read that plants like a soil water suction of 30kPa to 200kPa and that some soils, like clay, can hold onto the water so tightly that the plants can't extract it. Is this hogwash or sound science?

Al may have the numbers handy, I don't, sorry. It is true that clay holds onto water pretty tightly, but it's also true that clay is the most productive soil type out there (for ground growing). In a container situation I have not seen any signs of drought stress from any plant when the turface was visibly moist a few inches down. In fact for houseplants I use hydroton balls which wick water upward to plant roots and it works great so it's clearly not being stingy with the water to the plants ;)

I didn't think it would be a problem since everyone uses it successfully. I was just wanting to confirm that what I was reading on the "internet" was true.

Also, any advice on how much bone meal to put into my fresh ground pine bark?

The bag says to put 1T per 4" of pot diameter every 6 weeks. If I were to put the bark into the big tubs I have I would add around 4.75T to them. Compound that 3 times to account for the time I will be letting the bark sit and I get 3/4 to 1 C. of blood meal per tub. Does that sound reasonable? BTW, the volume of the tubs is 2.25ft^3.

Thanks!

Bone meal breaks down so slowly in containers that you may as well call it ineffectual. I hope you'll consider using dolomitic (garden) lime in its stead, @ 1/3 - 1/2 cup/cu ft.

How much blood meal you can/should use depends on a variety of things, chief among them being soil biota population level, which determine how rapidly the nutrients become available, and soil temperatures.

Blood meal really encourages fungal growth in containers, but more importantly, it can be extremely difficult to manage in any media that contains a high % of organic materials; it breaks down very quickly & can burn easily; it also loses much of its N through volatilization (gas), and is very high in ammonium (ammonium toxicity becomes a major issue in soils below 55* or above 80*). High soil temperatures inhibit the conversion of ammonium to nitrate, and low temperatures exacerbate ammonium toxicity in organic soils at rates as low as 2 lbs/ cu yd. The cup (1/2 lb) suggested is enough to (by itself) supply maximum nitrification to more than 7 cu ft of soil (>55 gallons), and this doesn't take into account the added N from other sources. This makes the potential for extremely rapid delivery (and burn) very great, with no way to control the rate of delivery.

Al

Al,

I was definitely going to use the Dolomite in my mix. Your past advice has convinced me of that far and away. The blood meal on the other hand is just because I had some laying around from the days before I was reading up here. =)

I am only considering adding nitrogen to the ground bark to help accelerate, as much or as little as it may be, the composting process for the next five months that I'll be waiting to use it. I think I'd read somewhere on here where you said that nitrogen could be added to the ground bark to help it compost. I've been looking for that post...but I can't find it. So perhaps it was my imagination.

Overall, it sounds like blood meal may bring a few too many downsides to the party.

Thanks!