Question
My Dad always grew sunflowers with very large heads, he won our local show a few years running, well he died last year and we wanted to grow some sunflowers from his seeds he collected from the previous years sunflowers and enter the show in his memory but by the time we got ourselves organised it was a bit late for planting and they weren't big enough although one we entered did win bonniest sunflower, we would like to try again this year, but as we are novices, we don't know much about them such as best time to plant, what type of fertiliser to use, and when, we aren't really bothered about the height of the plant but we would love to get a large head, we still have some of Dads original seeds as well as some from last years flowers.  Any help whatsoever would be very much appreciated.  

Answer
Sunflowers grow in warm weather, so if you are in a location with cold (snowy) winters and warm summers, wait to plant the sun flower seeds until after last chance of frost. If you live in the south (georgia, south carolina, texas, etc) you should be able to plant soon. If you live in the middle of the country, northern east coast etc you should wait until May.

Plant shallowly in a well draining soil and keep the soil moist but not soaking wet (but never allow to dry out). The plants will grow in 7-14 days. You can start them indoors in small pots about 3-4 weeks before planting out. E.g. if your planting out date is May 20th (which is my New Jersey planting out date for tender plants) you would start them no earlier than May 1st. Give good light from a flourescent light bulb placed really close to the top of the plants (inches away) or a sunny window.

Outdoors, give full sun and stake the sunflowers as they grow. Indoors, give a diluted liquid houseplant fertilizer with every watering, and outdoors give annual plant fertilizer every months through the growing season.

Sunflowers are today mainly hybrids which means that the plants are specially selected to grow large flower heads. However, a few hierloom seeds do exists. Hierloom seeds should be carefully harvested as they may come-true-to-type. By this I mean that offspring from a mother plant may also produce new plants with same good characteristics (e.g. large flower heads, etc). Modern hybrid may produce large flower heads, but it will be hit-or-miss whether the offspring will be anything worth growing. That is the price we have had to pay for extensive hybridizing of plants. I recommend you try to grow several of the harvested seeds. If you are not happy with the result this year, then buy a package of large flowered sunflower seeds next year (hybrids). When you buy hybrids they usually tend to be quite spectacular (but their offspring which you may harvest yourself you can not always rely on).

Good sources for seeds are:
http://www.parkseed.com/
http://www.thompson-morgan.com/
http://www.harrisseeds.com/

You can today buy so many different types: large flowered, small flowered, tall, medium, low growing, yellow, white, brown, old fashion, etc, etc. Even a few hierloom types are still available.

If your own seed harvest from your father does not give desired results try above sources.

A few general tips for growing sun flower:
- warm soil, lots of sun shine = fast growth requiring lots of fertilizer (monthly) and lots of water. Need staking for the taller varities.
- cold soil, cloudy = not much growth if any. use water sparingly and do not fertilize.
- frost = death of sun flower
- lack of adequate light = tall plants, skinny plants, plants breaking easily and no flowers to speak off.
- too much light (not possible with sun flower).
- warm temperatures above 60F = good result
- tropical heat about 95F consistently = bad news !!

Once you grow the sunflowers, try to give them a south facing planting site. Then you can observe something really interesting. In the morning, the flower heads will face east and the head will follow the sun through the day ending up pointing west in the evening. Once I put a camera up in front of a sunflower and set the automatic timer to take one picture every 20 minutes. At the end of the day, there was a great slide show of a moving sunflower. Unfortunately, the pictures got lost in the move, but I may repeat this another day.

P.S:
The size of the sun flower heads is genetically determined. If you have hierloom seeds which produce same naturally, then make sure you harvest new seeds every year and keep them. If not, then you can buy the large flowered ones from the above sources.


Good luck