Question
I bought the seeds as I'm looking forward to beautiful cut flowers on my dinner table. I'm in London and the daytime temp at the moment is under 70F/18C

Do Calendula's re-seed themselves? Can I just leave them and will they surprise me with flowers next year?
Or do I have to pick seeds, if so where do I find them? What do I do with them?

I'm originally from Malaysia where you just fling anything into the ground and they grow!

Thank you.

Answer
I have not grown Calendula myself from seed.  So I checked to see what the sage, green-thumbed Marie Iannotti, the About.com Gardening consultant, would advise.  She points out that these plants can be expected to bloom from seed within two months.  Here's her About.com website on the details:

gardening.about.com/od/herbsspecificplants1/p/Calendula.htm

Mother Earth News calls this 'one of the easiest annuals to grow from seed'.  On genetic matters, I can say I am well experienced, and this is unfortunately not so simple as you would think.

Generally speaking, Calendula officinalis cultivars are expected to re-seed every year.  But I must also point out that this really depends on which Calendula you are cultivating -- and this applies to anything you want to grow from seed, Kumari.  Hybrid flowers are obtained by crossing 2 different plants to get seeds, which are then planted and bloom.  But this is not so predictable as you would think.  Although plants and animals normally have 2 sets of chromosomes, it is also quite common to find multiple sets.  They can then be hybrids that are 'diploid' (with TWO sets of chromosomes), etc.  Do this enough and you end up with a brand new species.  One of my first projects in botany, many years ago, involved testing the effects of a chemical called Colchicine on the genes of a marijuana plant.  When you start multiplying the number of genes, you tend to get plants with some outstanding and desirable mutations -- bigger flowers are especially prized.  (Or, if you're growing marijuana, you would be interested in boosting the production of THC.)

What does this have to do with your biennial Calendula, aka 'Pot Marigold'?

If yours is a species, it would most likely have a modest appearance and average vigor.  But if it is a hybrid, seeds you obtain from the plant (after it is crossed, preferably au naturale by your local Bees or Moths) may well be sterile.  Or they may not, and if they are successfully grown they will most certainly look different from the parent -- 'expressing' genes that lay recessively in its secluded genetic DNA, out of sight, and then brought out in the next generation.  Could be lovely.  Could be forgettable.  You'd have to see.

Some polypoids on the other hand are sterile no matter what.  Again, you'd have to see.

Certain worth a try.  Odds are, they will re-seed so much you will start to wonder if this was perhaps something you should not have wished for...

For reference, print out this handy 'Grower's Manual for Calendula officinalis' by the official United Kingdom Dept for Environment, Food and Rural Affairs:

www.defra.gov.uk/farm/crops/industrial/research/reports/Calendula%20Manual.pdf

They note that Calendula seed sown outdoors in April will usually bloom by mid-June, depending on the hybrid.  Your tax dollars at work.  Best regards from Long Island, New York, USA,

THE LONG ISLAND GARDENER