T U B E R S

I start about 10th January and sort out the cutting tubers ready to box up. The very small ones, thumb nail size and under go on immediately, if you don’t get them on they will be drying up and I think they are more difficult to start. I put them in seed trays (plastic ones) in a mixture of half peat and half course sand, I give them a good watering and put them on the bench with a bottom heat of 65oF – 70oF greenhouse temperatures is between 55oF and 60oF.

The rest of the young tubers go on second half of January and the old ones, second half of February. I treat them all alike as far as planting is concerned. I leave them all with their tops showing level with peat and sand, this way you can watch for any white fungus appearing on a tuber and you can take it out, scrape it, dust with Benlate or Captan and replant it, I give them a spray over with water every other day to keep the crowns moist but not soaking as I think a lot of tubers are lost by being covered over with wet starting medium.

As soon as the cutting tubers make good root growth I start potting them into 3 ½” clay pots in my own version of John Innes. I use a fish box as my measurement and take 8 boxes of soil (usually mole hill) 2 boxes of peat, 2 boxes of leaf mould, (beech which I sterilise) 2 boxes of sand and to this I add 1 lb of John Innes base and 4 oz of ground limestone. I only pot the cutting tubers into this, the older tubers get an extra ½ lb of John Innes base and another 2 oz of ground limestone in their mixture. When potting up the older tubers I try to keep the pot size to 5, 5 ½ and 6 inch pots depending on the size of the root growth. This means when I do my final potting I can use 7” and 8” pots. These last few years I have had some old tubers which made their first potting into 7” and 8” pots ending up in finals of 9” and 10”.

This year I am going to use more young tubers and do away with the old ones, therefore I will get more plants in the greenhouse, I normally I would only get a dozen plants in the space available.

When all the final potting has been done, you can sit back and watch them grow for a spell as there is only watering to contend with. As I said earlier, I only grow in clay pot, therefore, watering is quite straightforward, plastic pots are the opposite, you must be very careful not to over water, especially just after re-potting.

Plants should not be growing steadily, but about five to six weeks after final potting there should be a real surge of growth, as the roots reach the side of the pots. Cuttings should be taken as they become large enough and if not required for cuttings or flowers, side shoots should be rubbed out as they appear. This is also the time to begin feeding for you must try and keep that surge of growth.

I use Maxicrop at the rate of one level teaspoon to 2 pints of water. The 2 pints of feeding is given to 6 plants in 6” pots, or to 4 plants in 7, 8, or 9 inch pots. I feed them at this strength twice, (1 per week) and then I double my Maxicrop and feed weekly until flowers are almost out. I believe myself that Maxicrop makes the colour run in the picotees, but it compensates by making the self colours richer.

Members always ask, how many times do you feed your begonias? Well, normally I feed about four or five times. Timing the flowers for the Show is the big problem, varieties vary from almost 8 weeks down to 5 weeks, from size of 5 pence to full out, some greenhouses come quicker, some slower, but the biggest controlling factor is the weather, so in actual fact we are only trying to guess what the weather for the 40 days before the show will be.

Personally, I am trying to stagger my flowers from 7 weeks down to 4 weeks, the first batch which are being given 7 weeks will include quite a few of the following:-
Guy Chart, Roy Hartley, Melissa, and Rose Princess which is always slow with me. The 6 week batch will take in all the varieties and will be the largest, the 5 week batch will have most of the Red Admirals as they come very quickly, also some Mary Heatley’s which I find edge very quickly when full out, the 4 week batch is just in case the weather turns out like last year, (it’s like trying to perm the treble change).

When I decide on the bud I want on the young plants, I take out the growing point at the same time, so there is no second change, although the plants are only last year’s cuttings when you take out the growing point they start to throw up basal growth, I think these should be left on as they act like a safety valve and this does away with double centres and coarse flowers. Last year after Ayr show I struck about 100 of these cuttings and most of them made small tubers by mid December.

After flowering I water about twice per week until the end of September when I stop watering completely. I then let them die down naturally, and by mid to end November most are ready for knocking out of their pots. When they are given a good brushing and the piece of the old stem is removed, the tubers are then laid out on the greenhouse bench and left until planting time at the beginning of the year.

I go over them occasionally and check for rot, but except for Avalanche, which I find hard to keep, I don’t lose very many.

The cutting tubers are kept growing until mid December then given the same treatment, the temperatures in the greenhouse during this time is kept between 40-50oF approx, if you find the cutting tubers very small put them back in the pots and cover them over with dry soil and they will keep better.

We are now back to the beginning again, so my tale is finished except for a paragraph on Pendulas.

In the first article I told you to leave all the shoots on your pendulas, keep them growing on until you get the first flower bud, then cut all the stems down to below a leaf joint showing an eye, so if you had four shoots you have four cuttings. The eyes in the leaf joints below where you took the cuttings will now grow on and you will have 3 or 4 shoots where you only had one. When the side shoots show bud, nip out their heads and they will send a further lot of side shoots which are the ones that will give you your flowers. If you want them for a special show, allow between 5-6 weeks from bud to full flower and you won’t be far out.

Just a word to end with. The cuttings only make very small tubers with me (some about the size of a pea), but don’t be disappointed for they start quite readily and grow on well.

Bill Dodds.