I have not tried Al's 511 potting mix, just other commercial mixes. My biggest problem is remembering to water them plants. Except for the watering issues, the plants do not care and they all seem to grow well. I do not have pests (knock on wood) so I have not raised them on bricks. That is the only reason I have heard for raising them. I cover the bottom with a mash to prevent pests from getting "in" and that is it. To keep the soil pH alkaline enough, you may be better doing frequent soil tests and not adding lime since you may get pinkish color when the potting mix is neutral. But then again, the lime may counteract the pine bark mulch and net to neutral pH which would end up giving you a pink with some mopheads. Hard to tell, you may to just try and get a soil pH test kit and use it often to monitor and tweak things. If you do, post the results. It would be interesting to know how well 511 worked.

If you put your containers in an area where there are trees then you may want to raise them up with bricks or rocks so tree roots do not invade the pot.

Thank you both, great info. I am going to do half in 511 and half in a container mix and monitor the results.

Will follow up with the results!

Wendy

5-1-1 IS a container mix - it is just more efficiently customized for good plant growth than are most commercial potting soils. It should work perfectly well for your hydrangeas.

btw, the lime will encourage pink/red coloring. It is sulfur or more acidic soils (and available aluminum) that produce bluer flowers

Thanks garden gal,I had my colours mixed up! Too much late night garden reading!

Wendy