Sunflower belongs to a group of plants described as being facultative long day bloomers. What this means is, sunflower will eventually bloom during the 'short day' period of the life cycle, so long as cultural conditions don't prevent it. Day length/photoperiod impacts the blooming of most plants. Actually, it's the length of the night that triggers photoperiod blooming responses, but that's another discussion. Sunflower blooms faster/better when day length is longer than about 14 hours, but as noted, WILL bloom under short day conditions (when the dark period is longer than the light period) - just not as readily as during long day stretches. You don't say where you live, but if there is danger of their freezing within the next 2.5-3 months, I wouldn't bother planting, as frost will take them before they can reach bloom stage. So sorry about your brother. Al

http://ezinearticles.com/?How-to-Plant-Potatoes-Successfully&id=1379496 "Depending upon the zone where you live, this will determine the best time to plant your potatoes. If you live in USDA zone 6 your potatoes should be planted from 2 to 4 weeks before the last frost is expected. The temperature of the soil should be approximately 40 degrees Fahrenheit. If you live in either zone 7 or 8, the best time for planting potatoes is in February or March. It is best to choose varieties that will mature long before the hot summer months set in. If you live in the southern region of the U.S., you can plant your potatoes in the latter part of September. Your crop will be ready for harvest in December and January."

I'm going out on a limb here, since I live on the other side of the puddle, but over the past few years I have found that one has to rely on instinct more than the instructions given on the packet as to when to plant out. 'Seasons', as such don't seem to exist anymore... we've had November days that were up into the 70's, and yet have had to turn on the heating in the house in late May. Summer flooding has become a real problem in parts of the UK, and last February we had snow in this area for the first time since 2003. Growing has become a lottery unless you are using a glasshouse, and every year brings the question of "what might actually produce a crop?". My pear tree hasn't fruited well in this millenium, last year we had a meagre plum crop ( nothing the year before )... runner beans did well, but tomatoes were a waste of time! I'm glad I'm starting to lose my hair otherwise I'd be tearing it out! :-)

Borage will not overwinter in zone 5, but it certainly will self seed. I would guess it would set seed prior to winter, depending on how early your frost hits. I would throw the seed down. There's a perfectly good chance some of the seeds would wait til next spring to sprout anyway.