Will potted Phoenix Roebeleniis grow during the Northwest European planting season?

[Zeni]

I got a potted Phoenix Roebelenii I want to keep outdoors (south facing, no shade) between April to October, but temperatures in my area are low during the spring/summer/autumn period (15 to 22 C / 59 to 75 F to  mostly).

Do they require substantial heat (+25 C / +77 F) to grow or will they also grow in mild conditions?

[TheMadScientist]

They should be "HAPPY" with those temperatures.  The more important topic for me is multiple drain holes in the container and a soil mix that drains well....then you can keep them moist without sitting in stagnant water.  I just collected ripe seeds from what appears to be a cross of Reclinata & Roebellenii planted for about 50 years.  Might have 12 heads that reach above the 2nd story apartment building.  I'm really looking forward to these germinating.

[oasis371]

It should grow just fine, remember, those temps are official temps recorded in the SHADE.  In full sun, on the south side of any structure, temps are MUCH higher, especially in black pots. 

[Zeni]

@TheMadScientist

The soil checks out. It is a mix of seramis (similar to perlite), fine pine bark, and regular potting soil. I am using rainwater to water it and I am careful with fertilizer (exact proportion).
 

@oasis371

My main concern was this Phoenix subspecies comes from the true tropics (Southeast Asia) and is usually only a houseplant in most of Europe, but I prefer letting it grow on my patio outside and only bringing it indoors or in the greenhouse for the winter. Glad to know that this is possible. 

I have seen potted Phoenix Canariensis grow fine here, but my worry was the Roebelenii would require substantial heat to grow. 

[Rickybobby]

You will be fine. That south facing sun will heat those pots up nice and stimulate the roots nicely.