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HOW TO GROW BULBS (LIKE WE DO)
Here are some basic pointers. (If
you would like a PDF download of these tips, click HERE).
However, the PDF file may not be as up to date as this page)
(We enlarge on these notes when we have the time! Last
updated September 23rd, 2013)
These brief notes are divided
into the following sections; click on any heading below to go directly
to a particular subject.
Gardening Tips takes
you to an article written by Nancy, who is the landscape architect at
the local Air Force Base.
Seed | Cleaning | Stratification
| Storage | Propagation
Seed Mix #1 | Moving Up | Soil
Mix #2 | Watering | Fertilizing
Harvesting | References
and Resources | Big Lessons Learned | Gardening
Click on any "Back
to Top" button to return here.
You know that its illegal to collect bulbs from the wild,
so you must grow them from seed. Here goes
You can collect seed yourself, or buy from collectors (some advertise
in the back of "Fremontia", the magazine of the California
Native Plant Society, C.N.P.S.).
You need a permit to collect from public lands. Each public agency
has its own system, average cost is $50, and there are lots of restrictions.
Quite a hassle. And of course, you need permission to collect from private
lands other than your own.
Responsible collecting. It is very easy
to overcollect; pods contain an amazing number of seeds.
One D. multiflorum pod might contain twenty seeds, one C. luteus pod
might contain one hundred and twenty. Think hard why you would want
more than a pod. So, use good judgement, take no more than 2% of a stand.
Never collect in consecutive years or when there has been a poor crop.
The easiest way to find seeds is to note or mark where the flowers
are in spring! Pods are usually brown and dry and very hard to pick
out. Do not rely on your memory, make copious notes, diagrams. Things
look quite different when everything is brown, and you are trying to
find brown pods amongst grass that has grown three feet since you found
the flowers. Find a pure stand far from similar species in case they
Some types of pods (e.g., C. monophyllus) inconveniently mature
upside-down, scattering their seeds as soon as they are
ripe, and making collection timing difficult. Other pods mature right
way up, and you can find some seeds at the bottom months after
they are ripe, if they are not shaken by the wind or animals.
Collect in paper or cloth bags, never in plastic, and label the
bag with at least location and date immediately.
Keep a detailed log! Set the trip meter at zero at a permanent
marker or sign. Or, use a G.P.S. positioning system. You can get a basic
one for as little as $100.
Let them dry out where there is good air circulation.
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We are processing small quantities here, so its done by
Some kinds of pods (e.g., fritillarias or lilies) are easy to
break apart with fingers; separate the seeds into a plate.
Some pods (e.g., ookows) are hard; you can break them up with
a rolling pin (slower, but better control) or in a food processor if
you put several layers of tape over the leading edges of the blades
to prevent damage to the seeds. Use 1second bursts.
Its not necessary to remove all the detritus, youre
not selling these seeds! But, it can get addictive for some folks.
Fine chaff can be removed by winnowing. While shaking the seeds
in a cookie pan with tall sides, or a bowl, blow over them (downwind!)
Pick out the larger stuff. If you shake the pan rapidly at a
slight angle, the seeds often settle to the bottom.
We also use a set of screens (6 different sizes are commonly
available from specialty companies, for example, Abundant Life Seed
Foundation, P.O.B. 772, Port Townsend, WA 98368, (360) 385-7192).
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Stratification (the breaking of seed dormancy) is a large subject.
There are some useful books, e.g., Seed Propagation of Native California
Plants, by Dara Emery.
Most native bulbs have simple stratification needs, either cold,
warmth, moisture, or in combinations.
Usually, the higher the source elevation, the more seeds need
cold stratification, which can be done in the fridge. The lower
elevation (below 2000') seed needs no stratification at all and germinates
quickly with the onset of the rainy season.
Weve never tried seeding green(seeds that have
not yet gone into dormancy or "waiting mode", we suspect high
temperatures with moisture will lead to disease. Why bother?
Most local seeds do fine in local conditions, our rain/freeze/thaw
cycles are sufficient if started in fall
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Excess seeds can be stored in refrigerator or freezer, but they
must be dry (8% moisture is ideal) first. You can use silica gel to
remove and regulate moisture.
You can buy professional containers that have a double seal;
heavyduty freezer bags are O.K.
Seed containers in various sizes are available from Southern
Exposure Seed Exchange, P.O.B. 170, Earlysville, VA 22936 (804) 973-4703
www.southernexposure.com. These containers will last the rest of your
Label them well! Worth keeping good records, so much easier to
look up what youve got than sorting through the freezer!
In our experience, storage time in the freezer varies. Flat lily
seeds up to 5 years, most others up to 7 years, sometimes more.
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Seed in FALL! Lilies especially like those warm, moist conditions.
Lower elevation species can be seeded later.
We seed in flats, grow for two years, then move into big bins.
Most reach flowering size in 3-4 years, lilies longer. Our experiments
where we sow directly into large bins are proving very successful,
we recommend this for all small growers. This eliminates the trouble
of transplanting later.
Not all seeds germinate the first year. Dont throw a flat
out for at least three years! This is particularly important with lily
seeds. Some species do all their development underground the
first year, and nothing shows above ground for all that effort, while
others will produce a tiny leaf.
We use seed mix on following page for all flats, except for desert
species which are diluted by half with clean sharp sand. If you are
using commercial mix, you can add sand or perlite to enhance drainage.
If you use our mix formula, break up the peat first, and premoisten.
If you are doing much mixing, use a cement mixer. This is the
most accurate way to mix quantities, by far. Otherwise, it is very hard to mix in things like trace minerals evenly.
Adding enough moisture to wet the mix, but not so much that water
squeezes out if you compress it in your fist, use the following formula:
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SEED MIX # 1 for seeding, using (3) 5gallon buckets:
2.5 cu. ft).
1 PEAT, 1 VERMICULITE, 1 PERLITE (1 bucket each to make 3 buckets total)
+ 8.5 oz Osmocote Pro 13-10-13 with IBDU and micronutrients, or equivalent
+ 4 oz rock phosphate (this stuff is mined, and is released over a very
+ 2 oz dried kelp (these last two available locally from Peaceful
Valley Farm Supply on IdahoMaryland Rd in Grass Valley, CA)
Prepare clean flats (see our note above about sowing directly
into big bins; if you go that way, sow into an inch of this mix laid
over seed mix #2, below). We use 17" by 17" commercial type.
Place 18" by 18" heavyduty landscape fabric in the bottom,
to stop soil coming through and roots coming up. (Rolls often are usually
36" wide, so saw the roll in half with a hacksaw first).
Fill flat with mix to 1/2" of top, and tamp down with a
Spread seeds thinly and evenly. You want to avoid later transplantation
Cover seeds with 1/8" (smaller seed) to 1/4" (larger
seed) of mix, and tamp down again.
We cover the flat with a mulch of pine needles. You can gather
them in good quantities from the side of the road after the second or
third good storm of the year. Being run over a couple of times makes
them soft and easy to lay! Mulch stops heavy rain from knocking mix
out of the flat, moderates the temperatures. Shoots grow through fine.
Water in thoroughly. You may have to water during winter if there
is no rain for a few days; test the top of the mix.
Use two labels (we use colorcoded Dymo tape on a stainless
steel strip for one) on each flat, and keep records! We put one
label at one edge, just below the surface, where it is protected against
being pulled out and the weather, as a back-up for the other one.
Put flats in the same conditions that they will grow in, similar
to where you harvested the seed from.
Once containers dry out in late spring, protect them from hot
sun by moving to shade, or cover with shade fabric.
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MOVING UP (after two years)
Some bulbs are big enough to plant out in your landscape after
two years (though they wont be flowering size). We recommend that
you do this if you can, you'll get a better survival rate.
We, however, move our bulbs up into big bins and use a different
mix which drains faster and is cheaper, too. If you are growing smaller
quantities, you can just plant the seeds (in a layer of seed mix over
the regular mix) directly to the big bins, and save yourself the movingup
job. Note: in later years, we changed to seeding into the final bins, and this worked fine, and it saved a lot of work.
You can use good commercial potting mix, such as Supersoil, instead
of our mix. You can increase drainage if necessary by adding perlite,
decomposed granite, or sharp sand.
Note that black flats, pots or bins can get very hot in the sun.
Move to shade, or cover with shade fabric in the summer.
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SOIL MIX # 2 for big (ours
are 26" x 20" x 6", filled to 4 1/2") bins, using
(6) 5gallon buckets: 5 cu. ft)
1 PEAT, 1 PERLITE, 1 clean sharp SAND, 3 COMPOSTED BARK (6 buckets total)
+ 17 oz Osmocote Pro 13-10-13 with IBDU and micronutrients, or equivalent
+ 8 oz rock phosphate
+ 4 oz kelp
You can add more perlite or coarse sand to improve the drainage
for desert, alpine types that grow on scree or gravel.
We transfer the bulbs before the rains, usually in October, using
the following quick and dirty method.
On your potting bench, take a 17" by 17" plywood board,
lay it on the flat, and turn them upside down, as a unit.
Remove the flat and landscape fabric.
Flip the board and mix back over onto the big bin. Dont
worry, youll get better! The bulbs are now right way up.
Spread out the mix in chunks, then fill in the cracks
with fresh mix. You are doing this when the bulbs are dormant, so they
are not disturbed.
Wash and disinfect the flat and landscape fabric by rinsing off
soil, then soaking in 2% chlorine solution for a day. They can be reused
many, many times.
Please note these changes: In 2001, we modified
our soil mix because we moved to an area with higher rainfall (50),
and needed better drainage. To the above mix, we add 1/2 bucket 5/16
granite chips, used for Chip and Seal paving. This has helped
a lot with drainage, but makes for much heavier bins. So we have started
moving to the smaller Anderson propagation flats, (Anderson Die &
Manufacturing, 2425 S.E. Moores Street, PORTLAND, OR 97222, (503) 654-5629),
which are 17 by 17 by 5 inches, with a strong mesh bottom which drains
excellently. These are very durable, and are even used as lobster traps
with an indefinite lifespan. They weigh 1/2 of our large bins when filled,
about 20-25 lbs. We still line them with landscape fabric to stop the
bulbs pulling themselves through, and to discourage roots coming in
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Flats dry out easily. They must be kept moist from seeding time
until consistently hot weather arrives, including during winter. The
bins, which have a much higher volume to surface ratio, rarely need
winter watering. Start watering November 1 if the rains havent
started. Water until hot weather starts. But remember, most of these
bulbs dislike high soil temperatures and moisture at the same time,
so if this combination occurs, stop watering.
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After the second year, topdress flats each fall with slow-release
fertilizer. We use these amounts:
+ 17" flats1 LARGE tablespoon Osmocote-type fertilizer each
+ Big Black Bins (1.35 cu. ft = 2234 cu. in)3.2 tablespoons Osmocote
When watering, we use Miracle-Gro in a Miracle-Gro mixer/dispenser
on the hose every two weeks, from March until drying out time (see Watering)
at HALF strength. Don't leaf fertilize on hot days, and follow up by
watering the next day.
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Bins dry out before August and bulbs are dormant. Empty bins
out on the potting bench, and sift through mix carefully. Be careful
of dust, wear a mask if necessary. The sizes of the bulbs will vary
dramatically. The littlest bulbs can be hard to find (the size of rice
grains and sometimes the same color as the mix).
Note: some dryland species form bulblets from the base, and some
form offsets on the stem. Separate, and grow on.
Sort into sizes, replant little uns back in same mix after
incorporating fresh batch of slowrelease fertilizer.
Of course, do not reuse mix if there has been disease!
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BIG LESSONS LEARNED (over 20 years!)
It took us years to learn this lesson… Use the heaviest-duty landscape fabric you can find to line your Anderson bins. The majority of these bulbs can pull themselves down right through regular landscape fabric into the soil below. The next season, they cannot find their way back up through the same hole, so they die. We lost thousands upon thousands of bulbs before realizing this (we thought the holes we saw were from tree roots or insect tunnels).
Do not grow bulbs beyond five years in the same bin. The losses become increasingly heavy. If you are growing these as a hobby to plant out on your land, they are big enough at two years old. Plant them out then, the survival rate will be the highest at that point.
• Do not use 'natural' fertilizers. We tried compost, compost tea, and organic fertilizers. What may be good for other plants is death to native bulbs—probably they have little resistance to unfamiliar microbes.
Do not be tempted to use the offsets produced by the Dichelostemmas. Use fresh seed instead. Give away or plant out those offsets instead.
• Replace any labels over four years old. Use two labels per bin, with one pushed down the side as insurance. Of course, you are logging all your seeding, aren't you?
• The ideal growing situation is: lots of sunshine in the spring, some way to shade the growing bins as soon as the plants have died back. Homeowners can move the bins under the porch, larger scale growers must use shade fabric. The worst case scenarios are: moist soil and high temperatures at any time of the year, and: cooking the bulbs in black containers in the sun. Do whatever is necessary to avoid these scenarios!
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REFERENCES AND RESOURCES
Growing California Native Plants, by Marjorie Schmidt
Complete Garden Guide to the Native
Perennials of California, by Glen Keator
Seed Propagation of Native California Plants, by Dara
Wild Lilies, Irises and Grasses:
Gardening with California Monocots by Nora Harlow, Kristin
Jakob, editors (University of California Press, 2003)