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Raising Bromeliads from Seed

 In the two previous articles on bromeliad seed, we talked about the types of seed and how to go about collecting, gathering, pollinating and hybridizing. We also talked about the reasons for collecting bromeliad seed, and how important it is to continue the Society's Seed Bank, not only for present members, but also new members coming along, remembering we all lose plants from time to time so growing from seed is also a good way to replenish our stocks.

Bromeliad seed, is referred to as tropical seed, i.e. similar to anthurium, and crotons etc, and we are talking about the three subfamilies here. There are some special requirements for their successful germination, and if we can supply these requirements, then you will find that raising bromeliads from seed can be both relative easy, and rewarding.

I have observed a number of methods that members use to raise seed and we will discuss some of these. My talk was based on the way that I do it and if you would like to try this method, well and good, but remember an old adage - if you are having 100% success rate in your seed raising, then stick to it, we do not have to re-invent wheels.

The first two pre-requisites are heat and light. There have been many seeds lost because members have not given the seeds bottom or surround heat, or have put them in a dark place. Bottom heat is where we have a heat pad and this can be thermostatically controlled or the same for a heat blanket. The light can be artificial as with light bulbs or fluorescent, or it can be day light as in the garage or under the house with an outside window. Surround heat is a hot box with say a 15 to 40watt light bulb. The temperature in both cases should be around 75 to 80°F or 20 to 25°C. Always use a thermometer to guard against over temperature, remember 80°F or 26°C is maximum.

Before we discuss the different methods, there is a very important step we must all take. As we are dealing with electricity, and water or dampness and electricity DO NOT MIX, you will need to have some protection. If you have an isolating transformer OK, if not, you should purchase an R.C.D., or Residual Current Device. There are a number of these on the market. I use both HPD Portable heavy duty, safety switch Cat.D5101, and a PDL Powerguard Cat. 955. If you want to go a little further, you can purchase a RCD three pin plug power point single or double and change your present power point for the RCD. If you are doing this under the house, it is not difficult to do, but if you are not sure, then ask a friendly electrician.

From the pictures you can see that there are a number of methods one can use. In picture 1. we can see a standard heat blanket that is thermostatically controlled, with fluorescent tubes above. The lights are on a timer and go off at 10 pm and on at 6 am, as it has been proved that a period of rest or darkness is beneficial to the seedlings. You can also use 'Glow-Lux' tubes, although they are dearer than standard tubes.


In picture 2 we see a hot box and this is surround heat. This idea, came to us from Avon Ryan of Whangarei and can be made in a variety of sizes. This one is a polystyrene box with a lid from the vege shops, in which our brussels sprouts come up from the south. The lid is cut out and covered with plastic sheeting. On the long side, a standard light fitting is attached with a cord and plug and the fitting glued in with Selley's No-nails. A large tin, say an ex-fruit salad type is attached and holes are drilled around the out side and this helps to dissipate the heat over the whole box. This size will allow you to have a number of seed pots germinating at once. If you want a larger size, you can fabricate your own from 40mm thick polystyrene sheeting from your local building merchants and it can be glued and nailed with clouts and Selleys No-nails.


For the seed containers you can use ice cream or margarine containers or whatever you like. I now use clear plastic containers with lids, 10cm high x 12 cm in diameter from Pay-less Plastics where they are very cheap.

You may even be lucky like me, and find an old Coca Cola shop display cabinet in which I replaced the cooler part with fluorescent tubes (small ones) in two banks of two, to give the right temperature. Perhaps you can use an old fridge. With the shelving, these make excellent hot boxes with plenty of room.

The mixture I use is 60% Bloom potting mix and 40% pumice sand. The mixture is sterilized with boiling water, drained and spooned into the containers when still hot and this helps to keep everything sterile. It is then flattened down to form a flat surface for the seed and allowed to cool. The next day the seeds are sprinkled on the surface and the lid replaced. Incidentally the lids have had a hole drilled in the top and this has a cotton wool bung to prevent contamination from getting in. I cannot stress enough the importance of cleanliness and sterility. It is all very well to get, say, a dozen seeds to germinate, but, that should tell us that something is not right and we should strive for 100% germination and we will only get that if we follow the rules.

Some important points:

The seed should be as fresh as possible. It should be clean and washed and if in doubt, washed again. The containers should be cleaned by washing with boiling water. The mixture should be sterilized, and placed in the container with the lid on as soon as possible. Before closing the lid on the seed containers, give a few mist sprays of Virkon which is an excellent anti-bacterial and fungal disinfectant, but there are a number of others like Benlate, Chinsol, and Physan 20. With Virkon it is 1gm to 1 litre of warm water and the others as per instructions.

Fertiliser? Look for a high potassium based fertiliser such as Yates Thrive N.P.K 15-4-26, or Phostrogen N.P.K 14-4.4-22.5. If you like using a milder liquid type you can use Watkins Bounty or Nitrosol, in any case it is advisable to alternate between the types. Twice a week, or when necessary, mist spray your seedlings at half strength mixed with Yates Bravo for a fungicide. This is an added precaution against fungal problems. If you continue to use the Bravo, your die back or damping off days are over. This is mixed up in a large container with hot water from the hot tap and allowed to cool before use, so that you have plenty on hand.

If you follow this procedure, you should have germination in about 4 days and plants to prick out in about 5 months depending on the genus.

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