The Bulb Maven

Sowing Seeds

I have poted before on sowing seeds, and one post can be seen here:  http://thebulbmaven.typepad.com/the_bulb_maven/2008/12/sowing-seeds.html  I think, however, it is worth a recap, since winter is the time that most seed sowing goes on at Telos.

All seed of species native to the western USA is sown in the fall. I used to direct sow the seed into pots, but found a much better way of doing it.  All seeds are put in plastic ziplock bags in damp vermiculite, then put in the refrigerator.  I usually do this in late October, and definitely want it all done by the end of November, earlier is better.  In this way, in just one day I can have all the seed bagged up and refrigerated instead of mixing mountains of potting soil, washing pots and filling them, then carrying them all out to the greenhouses.  Seed will vary in the amount of time it takes for them to germinate, so I check the bags weekly and pull any that show any sign of germination.  Some Calochortus seed germinates in two to three weeks, other species (especially from high altitude) can take as long as four months, so the actual sowing is spread out over the entire winter.  By the end of winter, I discard any bags that haven't shown germination. Usually, if the seed is non-viable, it goes moldy.  Above is a bag of Calochortus seeds ready to sow.

Seed of South African species are also sown at the same time of year than the natives, but these seeds need a diurnal swing of at least 10 degrees Fahrenheit.  If you refrigerate them, they don't germinate, so these ones are sown directly into the pots in which they will grow.  South African Amaryllids, such as Brunsvigia, are sown as soon as the seed is ripe.  If I am receiving seed from South Africa, that means as soon as I get it, even though that means the seed is germinating at the 'wrong' time of year as far as our seasons are concerned.  It doesn't seem to matter, they do fine, and will grow continuously without going dormant for the first year.  Such seed can't be stored, they are like small peas and will even germinate on the plant.

Seed of South American Amaryllid species are also sown when ripe.  They are not like the South African seeds, having a papery shell, and can usually be stored for fairly short periods. Up to three months is perfectly safe.  These species I also bag in vermiculite and keep at room temperature.  There are other ways of germinating these seeds, such as floating them on water, but I don't find I have better results that way.  I have also tried folding seeds in damp paper towels, but you really have to keep an eye on them, if you let them go too long the radicle will penetrate the paper towels, and you have a mess on your hands.  Other South American species that are winter growers, such as Leucocoryne behave like our native bulbs, and are treated the same way.

 

As soon as any germination is seen, the seeds are sown in pots or large trays.  I live in a valley with high humidity in the winter, not the best conditions for seed survival.  It is extremely important to have good air circulation for the developing seedlings, or you can lose the lot to damping off fungus.  I have overhead fans in the greenhouses, but, more important, are the fans that blow air directly across the seed flats 24 hours a day.  The trays are topped with pumice to keep the surface dry.

Here, at Telos, seed sowing is the major task for early winter, but even for hobbyists it can be very challenging and fun.  I lost so many precious batches of seeds early in my career as a bulb grower and still occasionally have failures, usually due to severe weather.

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El Nino

 

It has been a while since I have posted on the blog, and I apologize for that. Most of the winter has been spent dealing with the ravages of El Nino.  We have had about 35" of rain here locally, almost all of it in the past two months, and since I live in a valley, there has been extensive flooding.  Two years ago we had had only four inches of rain around this time, so I really can't complain, but it does present challenges as far as keeping the bulbs healthy.

Here are some tips to keep bulbs going in the winter during very wet weather when humidity may be 100%.

 

 

 

• Keep the bulbs dry.  This may mean you don't water at all for extended periods.  Winter growing species, such as South African Oxalis, Gladiolus, Moraea, etc., and California natives may need some watering, but they can all do well growing very dry.
• Amaryllids should probably not be watered at all during winter.
• If you do need to water, try to keep the foliage dry.  I do this by trickling water into the pot, not using a spray attachment to the hose.  
• Keep fans on all the time.  If you have a greenhouse, there should be fans to circulate the air, but fans that blow directly onto the bulbs will help prevent fungal disease.  
• For winter sown seedlings, you MUST keep fans blowing across the surface of the flats continuously.
• Grow your bulbs in a fast draining mix with minimum organic material.  I use a mix that is high in horticultural pumice and supply nutrients through fertilization with a soluble fertilizer with micronutrients.  Do not fertilize unless bulbs are in active growth.

In spite of all these precautions there have been losses, mostly of seedlings.  My Gladiolus seedlings seem to be the most susceptible to fungal disease and I have lost most of those, but other species are doing well.

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Horticultural pumice

Horticultural pumice

I often receive questions about the potting mixes I use for my bulbs.  Needless to say, I vary the mixes according to the bulbs I am growing, with desert species being planted in a very dry mix that is largely composed of horticultural pumice, sometimes with no organic material at all, while bulbs that grow in forest regions will require more organic material.  I used to use a lot of perlite, a substance that is a volcanic material that has been heat treated to make it expand.  It is very cheap, light and readily available, and I used it to lighten the mix for the bulbs, not just to reduce the weight, a consideration when you are mixing tons of potting soil and moving hundreds of pots, but mostly to allow better water penetration and air to the roots.

From some of the questions I have received I think there is a little confusion about pumice. Horticultural pumice is light grey and is sold in bags or bulk.  A similar material is sold to use in horse stalls, and I believe it is called Dry Stall.  The horticultural pumice I buy is very uniform with a particle size that is about 2-5mm in diameter and it has no dust or fines in it at all.  The material for horses has a lot of fine material in it, and I don't think it is as suitable for growing bulbs.  The whole point of the pumice is to allow more air to the roots and faster drying of the potting mix, an essential factor when you are growing bulbs from dry regions.

Lava rock that is sold for landscaping and is used in paths and as a mulch is not at all suitable for growing bulbs.  It is high in minerals, some of which can be toxic to plants.  It is black or red.

Perlite is a useful ingredient for potting mixes, but I am phasing it out. I have become very sensitive to the dust, and even using a mask I get a lot of respiratory problems and eye irritation from it. It breaks down over time and floats to the top of the potting mix, which pumice does not.  It is far less expensive than pumice (about one fourth of the cost), but if I get better survival and less fungal rots with pumice it is well worth the price.

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Propagating Bulbs

A friend and his wife visited the nursery recently and commented on the trays I use to sow seeds and the divisions from twin-scaled bulbs.  They are actually meant to hold pots called bands, but when I bought them for that purpose, as soon as I saw them I knew I had found the ideal flat for growing bulbs.  They measure 15.75" (40cm) x 15.75" (40cm) x 6" (15.2cm).  I had long dreamed of a pot with a mesh bottom to allow even, rapid drainage that bulbs need.  I had, in the past, grown some seedlings in large round pots that were about 12" deep, but I had to drill extra holes in the bottom, and still the medium would be much wetter in the center than around the edges of the pots, and I often found I lost the seedlings in the center of the pot.  I have to line the flats with something so that the medium doesn't fall through, and I have used landscape fabric, but I am currently using row cover fabric cut into squares.  Any kind of mesh will work as long as it lets water drain evenly and rapidly.

I sow fairly large quantities of seed, so I will sow directly into the flats.  I have on occasion put dividers in the flats and sown two different kinds of seeds that need the same conditions.  The seedling bulbs are left in the flats for about two years then transplanted into whatever size pot they like.  Some bulbs, like Rhodophiala, absolutely require a deep pot, while others can stay in the flats if they are smaller bulbs and don't need the root room a deep pot provides.  Almost all my Oxalis are grown in these flats.

Here are some flats of Amaryllid seedlings covered with shade cloth.

 

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Hippeastrum vittatum

Hippeastrum vittatum is a very well-known species that also presents a great deal of confusion as far as its origins are concerned.  I always try to find out the origins and habitat of a species when I grow it, otherwise you are left guessing as to what kind of conditions it needs.  H. vittatum is described as A) being from Peru; B) being from Argentina; C) being from Bolivia and D) being from Brazil!!  It is also described as being a hybrid, not a species.

I think the confusion arises from the fact that it was collected in Peru but it was in cultivation there, and is not native to that country.  I have no idea why Brazil and Argentina got into the act, since it was collected in the 1800's in Bolivia, and described as native to Bolivia.  It has been used extensively as a parent in creating hybrids, so some bulbs that are circulated as H. vittatum hybrid have also added to the confusion, leading people to believe that it wasn't a pure species at all.

There is a great deal of variation in this species, especially as to the proportions of red and white in the petals.  I have two accessions, both grown from seed, one of which has much more red than the other.  Some have even more red, with only a small amount of white striping.  They are all lovely.  I grow mine in Mix #1, and do not provide extra heat.

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Hippeastrum striatum

If you look up Hippeastrum striatum on the internet, you will get thoroughly confused, since some entries say it is native to Hawaii, and others call it the Barbados Lily (rather a long way from Hawaii).  It is actually native to Brazil, but has made itself at home in Hawaii and, apparently, the Caribbean also.  This is a tropical species, and is very easy to grow as a houseplant.  In spite of its tropical origins, I do not give it extra heat, and it seems to thrive anyway. I grow it in Mix #1.  I have two forms of Hippeastrum striatum, the one that is usually available, growing to about 18-20" tall with large flowers, and a dwarf form that only reaches about ten inches, with smaller flowers.  The small one is very charming.  The upper picture is of the large one, the lower picture of the small one.

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Hippeastrum solandriflorum

I have only recently acquired Hippeastrum solandriflorum, and my bulbs are not yet mature, so I have no pictures, but photographs can be found on the internet, and it is quite spectacular, with elongated white trumpet shaped flowers.  It is from Venezuela, and grows in seasonally flooded savannah, experiencing a dry dormancy in winter.  I am growing mine in pumice in deep pots with about 1/3 of the bulb exposed.  They are on one of the heated benches. 

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Hippeastrum reticulatum v. striatifolium

Hippeastrum reticulatum v. striatifolium is a lovely little species from Brazil.  The flower stem is only about 12" tall, and the dainty flowers are pink netted with a deeper color.  The leaves are lovely too, with a bright white stripe down the center of each leaf.  I have H. reticulatum also, but it has not bloomed for me yet, and tends to stay dormant in the winter, while H. reticulatum v. striatifolium stays in growth year round on my heated benches.  I grow them in small pots, about five inches deep, in Mix #1 with a little added pumice.  I had tried them in larger pots, but they seem to grow better in a small pot.  The root system is not extensive, so the larger pot may have encouraged disease.

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Hippeastrum Part 4

Hippeastrum neopardinum:

Hippeastrum neopardinum is a magnificent species from Peru, with pink petals lightly netted with a deeper color.  I have the pure species, but the picture here is from a cross from seeds that I obtained from a friend.  They came labeled H. neopardinum x sp., so I don't know the other parent.  It is close to the pure species, and my H. neopardinum have not bloomed for me yet.  This has not been difficult for me, growing in Mix #1, but I do grow the species on the heated benches, and grow the hybrids on my regular benches, and I do not see much difference in their growth.

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Hippeastrum papilio:

Hippeastrum papilio

Hippeastrum papilio is an outstanding species from southern Brazil.  It is often available from the growers of hybrid Hippeastrum, since it hardly needs any improvement, but it has been used as a parent for some hybrids.  This has been very easy for me, growing in Mix #1 and needing no extra heat.

 

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Hippeastrum parodii:

Hippeastrum parodii

Hippeastrum parodii is from arid regions of Argentina and Bolivia where it endures hot dry conditions.  This species needs extra heat year round, and I grow my bulbs in Mix #3, but I also have some in pure pumice.  Growing with too much organic material or moisture will encourage rotting.  I have them in fairly large pots, and they have preferred to pull themselves below the surface of the potting mix, unlike most of my Hippeastrums that grow with the bulb exposed. They have a long dormancy, from mid-autumn through winter, emerging in late spring. Given the right conditions, they are not difficult, and they bloom regularly with me and set seed from their own pollen.

 

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Hippeastrum petiolatum:

Hippeastrum petiolatum

From Argentina, Hippeastrum petiolatum is a smaller species with brilliant orangey-scarlet flowers.  I grow it in Mix #1, and do not give it extra heat.

 

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Hippeastrum puniceum:

Hippeastrum puniceum

Somewhat similar to H. petiolatum, this smaller species is said to be widespread in tropical South America.  I have not given it extra heat, and it seems to do well without it, and I grow it in Mix #1.  I also have a double form of this little species, but it has not yet bloomed for me.

 

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A reader asked me to comment on light requirements for my Hippeastrum species.  I grow them in very large greenhouses that have a double film of plastic and are shaded with cloth made out of woven aluminum (this material is called Aluminet, and is more to reflect sun and reduce temperatures rather than provide shade).  The light in my greenhouses, therefore, is very even and diffuse.  I provide a little extra shade for some species that are near the south end wall of the greenhouse since they have suffered sunburn on the leaves on very bright days.  I think most of the species I grow, not including H. parodii and H. argentinum, need diffuse filtered light.  Those from conditions that are near desert like these two species will not be harmed by direct sunlight.  Air circulation, as in all greenhouses, is very important, and my greenhouses have automatic fans to circulate air.  My greenhouses are very large commercial type greenhouses, so if you have a smaller 'hobby' type greenhouse, it is imperative you have fans circulating the air, probably 24 hours a day.  If you want to see pictures of the Aluminet, go to Greenhouse Tips and scroll down.  This is much better material than conventional shade cloth since it doesn't heat up itself, and reflects the light back.

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Hippeastrum Part 3

Hippeastrum evansiae:

Hippeastrum evansiae

There aren't many yellow Hippeastrums, and Hippeastrum evansiae is probably the most readily available.  It is from Bolivia, and grows in hot, dry conditions.  It is rare in the wild, its habitat having being converted to agriculture, but is fairly easy to grow and propagate.  There are slight variations in the species, some having a pale orange central star.  Mine are greenish in the center. It needs to be kept warm, and I grow mine on my heated benches year round in Mix #1 with some added pumice.

 

Hippeastrum leonardii:

Hippeastrum leonardii

Hippeastrum leonardii is from Peru, but I am not sure of the conditions it grows in.  I am growing mine in Mix #1, and I have pots on my heated benches, and also on the unheated benches.  The heated ones have bloomed more reliably, so it seems to need extra heat.  I will try to round up more information on this lovely species.

 

Hippeastrum machupijchensis:

Hippeastrum machupijchensis

As the name indicates, Hippeastrum machupijchensis hails from the legendary Machu Picchu region in Peru.  Machu Picchu itself is around 8000', but the species also grows at lower elevations.  Since it is a high elevation species, I have not given it extra heat.  It offsets rather slowly, and I have not obtained seed from my bulbs.  I grow it in Mix #1, and keep it on the dry side, with 2/3 of the bulbs exposed above the surface of the mix.

 

Hippeastrum mandoni:

Hippeastrum mandonii

Hippeastrum mandoni is a magnificent species that hails from Bolivia. It is the largest Hippeastrum I grow, the flower stems reaching up to 30" and mature bulbs reaching 6-8" in diameter.  It needs a large pot, and I grow it in deep five gallon pots in Mix #1.  I do not give this species extra heat, and it has not been difficult to grow and flower.  I do keep seedlings on the mats for the first year, and they mature faster that way.

 

Hippeastrum macbridei:

Hippeastrum macbridei is another yellow species that comes from Peru.  I have no information on it, and my bulbs were acquired as very tiny offsets and have not bloomed yet, so I have no tempting pictures.  I am keeping them on the heated benches and they seem happy.  They are dormant in winter.

 

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