Is there any way that you could easily shade the green house during the day time? Even a white sheet over the top of it would allow sunlight to penetrate but would still reflect some of the light producing light waves. Does your greenhouse have some sort of ventilation so that some heat can escape during the day? I don't see much problem with the high temperatures you've mentioned, but as the days continue to get longer, and the outside temps more temperate, you may have some daytime temps that are simply too high. If not to both of those questions, I wouldn't worry about it too much. Large temperature differences can actually accelerate the ripening of some greenhouse crops! Especially citrus. By the way, all of the plant species you've mentioned do quite well in very chilly temperatures, as I am sure you've already discovered.

Wow... good point Al. I totally forgot about that. *whoosh* OW - Don't you mean.. lower to 6? If you have a way to directly measure the pH, then it doesn't really matter what kind of water you use. Just add the vinegar or acetic acid until you get the desired pH for the irrigation water. If you don't want to mess with the irrigation water, and you're okay with an imprecise change, you could use acidified cotton burr compost. It contains sulfur that is at least partially metabolized, and is often used as an acidifying soil amendment for Roses and Azaleas. It's commonly used both in the ground, and in containers. I don't know much about it, but you can find plenty of information online. I'm confused, are soil from your land in the containers? Or do you also want to try growing blueberries in the ground, and want to acidify the soil quickly? If you're using raised beds and adding a lot of new soil / amendments, most good nurseries sell an Azalea or Rose bedding mix that is fairly acidic. The quick fix is ammonium sulfate, but it's extremely hard for the non-professional to use properly, and is very detrimental to your soil biology. No amendment or product can really change your soil's pH permanently - you have to keep treating it at least every season.

Hi rjinga the plants look like they would be fine in those containers for another season. Keep in mind that Peat Moss and Sphagnum Peat Moss are two different things. What you need is Sphagnum Peat Moss. Blueberries like soil to remain damp but not soaking wet so you need a soil that drains well. They also like full sun. It would be unusual for your soil conditions to be acidic enough without being amended. They also like lots of organic matter. In most cases its good to work in sand to aid in drainage and well composted leaves for additional organic matter. Plus lots of Sphagnum Peat Moss and Cotton seed meal and granulated sulfur to aid in lowering the PH. From the looks of your plants it looks like you know all of that though as they all look healthy though a somewhat pale. The next next time you water them add some fertilizer and 1 Tablespoon of White Vinegar per gallon to it and I bet they will green right up.

I had potted strawberries, raspberries, and blueberries. I am in zone 7. In late fall I brought them into an unheated but enclosed porch, which seems to remain somewhere between 5-10 degrees above the outside temperatures. I wrapped all pots in bubble wrap and kept them against the house, and watered them lightly once a week on days when temps were above freezing to avoid the roots drying out. Everything looked OK until late winter when we had a deep cold snap and I covered the entire bunch with an old blackout curtain I had available, which served the additional benefit of keeping one of my cats from digging the soil, and kept it that way for probably a month or so until moving them back against the window side of the porch. When I was sure the last night of freezing temps had passed and I put them outside. Everything did well except the blueberry bush, which I'm pretty sure is dead. Looking for some resources, I did see that blueberries need some light, which surprised me since most outside bushes are advised to cover in mulch. I'm not sure but my conclusion is that blueberries do not do well in pots and if I want to try again, need to give them a chance in the ground. Or else i just focus on raspberries and strawberries.