1 – Growing from seed problem
I HAVE tried growing proteas from seed. Without exception, every germinated seed has withered and died within days of its appearance, presumably from “damping off”. What causes damping off? What factors or circumstances aggravate and contribute to the problem? What can be done prior to planting seeds in trays so as to avoid or lessen the possibility of damping off? I understand one can sterilise soil before planting by watering with a solution of potassium permanganate, Milton, Jeyes fluid or a Dynone/Benomyl cocktail, and even by heating the soil. If one does treat the soil in this way, how long should one wait before sowing the seed?
The commonest cause of damping off is soil-borne fungi. Many factors aggravate the problem: the spores may be present in the soil; seedlings which are crowded are more likely to be attacked than those which are spaced well apart and have plenty of ventilation; plants that remain wet at night are more likely to be susceptible; hot humid weather, especially at night lack of garden hygiene irregular watering; the soil should be kept evenly damp, but not saturated.
damping-off – a plant disease occurring in excessively damp conditions, in particular, the collapse and death of young seedlings as a result of a fungal infection. The disease is commonly caused by fungi of the genera Pythium (phylum Oomycota) or Fusarium (phylum Ascomycota).
Sterilizing the soil, either by baking in the oven or steaming it. Washing the seed pans with Jeyes fluid. Disinfecting the soil with Jeyes fluid. Watering the seed pans with Benlate (active ingredient benomyl) or Dithane (active ingredient mancozeb) after the seeds have been sown, and repeating two to three weeks later.
Drenching the seed pans with any remedy which has copper oxychloride in it, eg, Cupravit, before sowing the seed. Or using a Chesthunt compound as soon as the seedlings emerge. You can make up your own Chesthunt compound by mixing two parts of finely ground copper sulphate with 11 parts of fresh ammonium carbonate (by weight).
Store in a stoppered glass jar for 24 hours before using. Dissolve 28g in a little hot water and make up to 9 litres with cold water. Use this preparation as soon as you have made it up and water the seedlings with a fine watering can rose.
If the soil is drenched with the remedies mentioned above, and the seedlings are sprayed with Benlate or Dithane two weeks later, they should remain healthy.
The substances mentioned by you will not sterilize the soil: they will only disinfect it. This is what one authority says about permanganate of potash: “A deep pink solution of permanganate of potash is sometimes used to check damping off of seedlings; though Chesthunt compound does this more effectively”
Milton: it would not be advisable to use Milton as the chemicals in it could harm the seedlings.
Jeyes fluid is an excellent disinfectant. Prepare your soil mixture at least two weeks before use. Choose a clean surface such as concrete; spread a 10cm layer of sifted soil on this and saturate a solution of five tablespoons of Jeyes fluid to 4,5l water. Spread a second 10cm layer over the first and saturate that. Continue in this way until sufficient soil has been treated. Cover the heap with plastic sheeting or sacks for a week. Uncover and during the second week turn the soil several times to dry out and air. If the soil has to be kept, store it in clean plastic bags.
To sterilize soil put it in shallow pans in the oven at a temperature of 93 degrees for an hour. To sterilise by steam, bring about 3cm of water to boil in a large container, tip in dry sifted soil, put the lid on the container and steam for 20 minutes. Tip out onto a clean dry surface and, when dry, store in clean plastic bags until needed. Sterilised soil can be used immediately.
2 – Begonias from seeds problem
Begonia seed sown in the spring came up very well but the seed pan developed a hard surface with a greenish film. This apparently inhibited the growth of the seedlings and quite a few died off. These were grown in a ground-up bark growing medium and watered with seedling hydroponic mixture by standing the seed pan in water and occasionally spraying with a mist spray. They were grown in a warm room in a window that receives the morning sun. They were also sprayed with fungicide.
I suggest that next time you sow begonia seed you use the John Innes seed-sowing mixture, made up as follows: two parts good garden soil sifted through a 9mm sieve and, if possible, sterilized; one part imported peat or well-made compost sifted; one part clean coarse sand (all by bulk).
3 – Strelitzia growing from seed problem
I would like to grow strelitzias from seed.
Sow the seed in spring in well-drained, friablë soil. Keep the seed pans moist at all times. The seed germinates best at a temperature of between 18 degrees C and 24 degrees C. Germination is slow; the first seedlings will only appear above ground after about two months. It is also erratic, which is why it is advisable to sow the seeds well apart so that the first seedlings can be pricked out without disturbing the others. Patience is the keynote to raising strelitzias from seed: not only is germination slow, but the seedlings take up to seven years to flower
4 – Seedlings damping off
I have lost a number of seedlings this summer and now my winter seeds are also dying off.
Your seedlings are probably “damp off”- which is caused by a fungus. Sterilize your soil either by baking it in the oven or with steam. To steam sterilise, put four or five centimetres of water (the amount depending on the size of the pot) in a large saucepan. Bring this to the boil, then tip in the dry soil mixture. Put the lid on and steam for exactly 20 minutes.
Tip the soil out onto a clean surface to cool, then put in clean plastic bags until needed
The best soil mixture to use is the John Innes No 1 made up as follows: two parts loam (good garden soil), sifted through a 9mm sieve, and one part peat moss. If this is not available, use well-made compost, one part clean coarse sand. When you have sown your seeds, water with a solution of Dithane or Benlate and repeat in 10 days’ time. Keep the soil in the pans evenly moist, but not saturated. The day before pricking out the seedlings, water them with a solution of magnesium sulphate (epsom salt), and a heaped tablespoon to 4,5l water. This helps them stand the shock of being moved.
5 – Anthurium query
I HAVE managed to obtain some seeds after cross-pollinating some of my anthuriums. I was told that all I had to do was to set out the seed and sand or a mixture of sand and peat. This cannot be the correct method of raising these plants from seed as there was no germination at all.
It takes about a year for the seed to ripen and the seedlings take just as long to germinate. Sow the seed as soon as it is fully ripe in a mixture of sand and peat, just pressing them into the surface, as you were told. The seedpan/s must be kept in a close moist propagating case with a temperature of between 23,6 and 29,4 degrees C. The three important factors are high temperature (they are tropical plants) constant high humidity and the potting mixture must also be kept uniformly moist. Your seed may still germinate if you can give it the right conditions.
6 – Amaryllis from seeds
Recently we had red amaryllis in flower. They developed seed-pods, and when the pods opened, we planted the seed. Can you give us any information on them? Are they seeds? Will any germinate and how long does it take?
The plants do produce seeds and they should germinate in about 10 days if sown as soon as they are ripe and kept at a temperature of about 16 degrees C. The plants should flower in about three years. Do not overwater the seedlings in winter but, on the other hand, do not let the soil dry out, as the tiny plants do not die down.
7 – Jade vine seeds, how to plant
We have a jade vine growing in the garden. Recently, for the first time, the vine produced seeds in the form of a large pod. What is the correct way to plant these seeds?
Watch the pod on the vine and, as soon as it starts turning brown, place the foot of a nylon stocking over it and tie it at the top so that you do not lose the seeds when the pod is ripe. When it is ripe, collect the seeds and store them in an airtight container in a fairly cool place. The seeds must be dry before you put them in the container. In spring, soak the seeds in warm water overnight, then sow in friable, well-drained soil. Place the pan in a warm semi-shaded place and keep the soil evenly moist.
8 – Succulents and cacti
CAN YOU give me any information on growing succulents and cacti? What does one feed these plants? Can you grow them from seed? (We are in a semi-desert area.)
Because your climate is so dry, the nutrients are not leached out of the soil, so aloes, succulents and cacti need very little fertiliser. You can give aloes a little dry powdered chicken manure at the beginning of their flowering season. Other Succulents and cacti can be given two or three applications of weak Seagro fish emulsion during the growing season. Water before and after application.
When raising plants from seed, use a deep pan, about 150mm deep, so that the plants remain undisturbed until they have developed a good root system. The soil mixture must drain easily and the John Innes mixture would be suitable: two parts good garden soil, one part peat or compost and one part clean coarse sand (all by bulk). For succulents, etc, add another part of sand. To every 36l of this mixture add 42g of superphosphate and 21g of agricultural lime. Fill the bottom third of the seed pans with drainage material; place sufficient soil to come to within 50mm of the top of the pan, then finish off with about 30mm of finely sifted soil on top. Sterilize the soil and, when the pans have been filled, water with a very diluted copper solution three or four days before sowing the seed.
9 – Geranium propogation
I have a Geranium incanum growing beautifully in a large pot. It makes a lovely all-year potplant, but I have been unable to propagate it either by cutting, or seeds. There are lots of seeds and I would like to know how to get them to germinate.
Collect the seeds in mid-summer and sow them right away in the soil to which you have added some extra sand. It must be very well drained. The seeds should germinate in about a week.
If you would like to try cuttings again, put them in a mixture of two parts clean coarse sand and one part compost or peat and enclose the pot in a polythene bag. Put three or four small stakes around the pot to keep the polythene off the cuttings and inflate the bag by blowing into it, then tie the top securely. Place in a warm, semi-shaded position