Constantly Moist but not Wet

There are a number of plants, particularly those for partial shade such as astilbes, primroses, trollius and ferns that prefer or require consistently moist but not soggy soil. I have never had a garden that naturally provided these conditions and for years I struggled with all these plants. No matter how many times I told myself that this year I would remember to regularly water them, I always sooner or later forgot. Eventually I would notice the wilted trollius or crispy astilbe and pour on the water, but by then it was usually too late. I managed to keep the plants alive but they would never thrive.

When I started Good Scents I really wanted to be able to grow astilbes and trollius for cut flowers so decided to try to artificially create the conditions they need. The solution I came up with has worked surprisingly well and so I wanted to pass it on. I created large 4'x25' beds but the same system could probably be used on a smaller scale. The basic idea is to create a growing area that drains slowly but is also higher than the surrounding ground. This way the crown of the plants will not flood, but the roots will always have access to plenty of moisture. This is what I did:

• Construct a raised bed frame around the new bed using 2x8 lumber. If you are doing a smaller area you can probably skip creating the frame as long as the resulting bed is higher than the surrounding ground.
• Excavate about 18 inches of soil from the bed. This will make a big mess and yes, it is really hard work. When you are done the distance from the top of the frame to the bottom of the excavation is about 2 feet. If you aren't using a frame it will be about 18 inches.
• Line the bottom and sides of the excavated area with a single sheet of heavy duty (6-8mil) plastic. Plastic like this comes in 10 foot widths so there should be plenty if the bed isn't too wide. If you are using a lumber frame, the plastic should extend to the top of it.
• Use a pitchfork or other tool to punch holes in the plastic. I made maybe 5 pitch fork punches along the 25 feet. The holes prevent too much water from accumulating in the bed.
• Put the soil back into the bed, adding plenty of compost, peat moss and fertilizer as you go.
• When you're done the soil will be well over the top of the lumber frame. Much of this will settle so don't be alarmed.
• Plant your thirsty plants in the new bed and mulch.

Over a couple years I constructed 4 of these beds and have never before grown such great astilbes and trollius, not to mention other damp loving plants like primroses. I do water them occasionally when the weather is really dry, but for the most part the soil in the beds stays constantly moist but not wet.

One caveat - if your soil is dry because you have surface rooted trees like maples, pines, or cherries nearby, this method will probably not work because 1) excavating the bed will be impossible and 2) if you do manage to clear the roots from the bed, they will quickly return.

Starting Alchemilla (Lady's Mantle) from Seed

Alchemilla is fairly easy to start from seed but plants are readily available in small sizes in May at the Coleman's Market in Ypsilanti or other stores selling small perennials. The seed is a little smaller than poppy a seed, and like most tiny seeds it should be surface sown. The seeds are a little slow to germinate, taking 2-3 weeks to sprout, and the seedlings grow quite slowly at first. Because they are such slow growers, I started mine today.

Alchemilla (Lady's Mantle)

Alchemilla mollis is a plant usually grown for its attractive leaves. The grayish-green, fuzzy leaves are sharply pleated, hence the common name Lady's Mantle. The pleats and the fuzz cause dew and rain drops to bead up on the leaves in a way that is very beautiful and delightful if you've learned to appreciate the subtle pleasures of foilage in the garden. They grow very well in partial shade but will tolerate full sun and are often used as an edging in a perennial border.




Alchemilla mollis foliage


In additon to the pretty leaves, Alchemilla produces flowers, though I never appreciated them much until I started growing cut flowers. The chartreuse flowers are tiny but produced in panticles that are 6-8 inches long on stems up to a foot long. The overall effect in the landscape or a vase is a "foamy" filler, kind of like baby's breath only less trite and with a more interesting color. They bloom in the first couple weeks of June and the flowers are green enough to blend with pretty much anything.



Alchemilla mollis flowers

They arrive at the same time as the big, flashy early summer flowers like peonies and delphiniums and provide a needed gentle balance to them.

Chartreuse Alchemilla accents peonies, bell flowers, salvia and rose

Starting Delphinium From Seed

Delphiniums are easy to start from seed if you provide some simple requirements.

1. Use fresh seed packaged for this year. Older seed germinates poorly.
2. Chill the seed after sowing at 35-40 degrees for about 3 weeks.
3. Maintain darkness until the seeds sprout.

I sow the seed at 2-3 seeds per cell pack since the seed won’t be good next year and the package always contains more than enough. I cover the seed with about 1/8 inch of soil mix, mist with water, and then place the flat in a black plastic garbage bag. To provide cold I put the bagged flats in my unheated garage but you could also use a refrigerator. After 3 weeks of chilling, bring the flat back inside into a typical winter temperature room, 65-70F, but maintain darkness by leaving it covered with the plastic bag. Check daily for the first sprouts - they will appear in a week or two - and then remove the bag, cover with a humidity dome and place under lights.

Delphiniums

Delphiniums are one of my favorite summer flowers so I grow plenty and use them generously in bouquets. I mostly grow Delphinium elatum, which produces dense 1-2 foot spikes of flowers in deep blue, pale blue, purple, pink, white and lavender. Each floret in a Delphinium elatum spike has a white or dark brown contrasting center that is picturesquely called a “bee”. I also grow a few Delphinium belladonna, which produces less dense spikes in electric and pale, icy blues.
Purple and lavender delphiniums with salmon lily, white astilbe and daisies

There are numerous delphinium seed strains available but the most common Delphinium elatum series are ‘Pacific Giants’, ‘Magic Fountains’ and ‘Clear Springs’. ‘Pacific Giants’ grow 6 feet tall or more and are striking in a perennial border but they must be staked. For cut flowers I prefer ‘Magic Fountains’ and especially ‘Clear Springs’. Catalogs claim ‘Clear Springs’ grows 30 inches tall but mine usually reach 4 or even 5 feet and still do not require staking. I have less experience growing ‘Magic Fountains’ which seems to grow a bit shorter for me, around 3 feet. There are fewer Delphinium belladonna seed strains, the most common being the pale blue 'Clivenden Beauty', the dark blue 'Bellamosum', and the white 'Casa Blanca'.

I love delphiniums for cut flowers because of their shape, color and long bloom season. The tall spikes contrast beautifully with large round flowers like peonies, lilies, zinnias and dahlias. I also like them combined with lisianthus. I like to combine blue delphiniums with yellow, white or pink and the purple ones look great with orange. Most pink delphiniums are a kind of dusty rose color which looks nice with green nicotinia or deep purple lisianthus. Delphiniums sown in January or February will bloom in July of the same year, and the following year will flower at their normal time in early June and will rebloom in August and September. This means if you start some each year you can have delphiniums in bloom for two months or more of the year.

Starting Lisianthus from Seed

Most cut flower growers who grow lisianthus
start with plugs - tiny seedlings sold by large commercial growers. They do this because lisianthus grow extremely slowly for the first 3 months and are a little finicky about growing conditions when small. However, for someone with a small business like mine, starting from seed can be a good option. The pluses for me are it is cheaper to grow from seed than buy plugs and I can succession sow to get lisianthus for a longer season.




Pelleted lisianthus seed

Lisianthus take about 6 months to bloom from seed so I start the first ones in early January. I start some more in late February and a third batch in mid-April. The ones sown in January will bloom in July, the February sowing blooms in August and the April sowing blooms September and October. The commonly available seed varieties (Echo, Cinderella and Twinkle) are best sown in January or February.

Lisianthus seed are like dust, smaller than poppy seeds, so they are sold pelleted. Each seed is coated with a substance that dissolves when moistened. The pelleted seed are still small but can be handled individually. Because the seedlings grow so slowly I start them in 100 or 200 cell plug flats to to conserve space. Lisianthus seed are surface sown, misted with a sprayer, covered with a humidity dome and placed under the lights. The seedlings will emerge in 1 or 2 weeks but are almost impossible to see.

Seed Starting

Seed Starting
Every year I start thousands of plants from seed. Except for sunflowers, zinnias and a few others I direct sow outside, everything is started inside under lights in plastic cell packs. I use the same techniques I learned as a home gardener only on a larger scale. In later posts I plan to describe in more detail when and how I start different plants.

If you’re interested in starting a few unusual or expensive annuals or perennials this winter, the following describes the equipment and steps I use to start almost everything I grow.

Light Source
I use cheap 4 foot fluorescent shop lights you can get from any local hardware. You do not need special bulbs or grow lights, just standard cool white bulbs that will probably come with the fixture. The light fixture is suspended from the ceiling using light weight chains. This will allow you to raise the lights as the plants grow. Connect the fixture to a timer so it will be on 16 hours and then off for 8 hours.

Containers
I use plastic cell packs (liners), like the kind used to sell annuals in the spring. You can buy new ones or recycle used ones. If you reuse them, they should be washed in soap and water with a bit of bleach to kill any diseases. The 72 cell per flat liners are big enough for starting most things and you can fit two flats or 144 plants under one light fixture. You may also want to get plastic flats to hold the liners unless you want to have to handle each cell pack individually.

Humidity Domes
You can either buy or improvise humidity domes. These are clear plastic domes that will fit over a single flat. This will hold moisture in so you will not need to re-water the seeds until they emerge. You can also use plastic wrap or improvise with anything that is clear and will hold in moisture.


Flat, 72 cell liner and humidity dome

Growing Media (“Soil”)
I put “soil” in quotes because I use pre-packaged seed starting mix rather than real soil from outside. I do this because it is light, very well drained and sterile. Most of these mixes are composed of peat moss and vermiculite and/or perlite. If you use dirt from the garden then you must sterilize it by baking it in the oven because it is full of weed seeds and pathogens. If you go this route (I don’t recommend it) find directions on the web about how long to bake your soil and what temperature to use

Prepare Containers
To avoid compacting the growing media, you want to moisten it by watering from the bottom rather than the top. Fill the liners with grow mix and place them in a container of water. You can use a flat to hold the water if it has no holes. The water will be absorbed through the holes in the bottom of the liners – it will take about 10-30 minutes for the grow mix to become moistened. Once it is wet, remove the liners from the water and allow them to drain for a few minutes.

Sow the Seeds
Now sow the seeds in each cell of the cell packs. Different seeds need to be sown in different ways and you need to rely on the information on the seed package. Typically, very small seeds are just dropped on the surface and are not covered. If this is the case the seed package will say something like “surface sow” or “light needed for germination”. If the seeds are to be covered, the standard rule of thumb is cover with 3 times the depth (smallest dimension) of the seed.

Unless the seed is expensive and I want every possible plant, I usually sow 2 or 3 seeds per cell to ensure I end up with one plant per cell. If the seeds are very tiny, be careful not to sow too many. Under these indoor controlled conditions you will get very high germination and thinning tiny seedlings is very tedious.

After sowing the seed, whether covered or uncovered, use a spray bottle to mist the surface of the soil mix with water. This will ensure that the surface sown seeds are in good contact with the media and that the covered seeds are watered in.

Under the Lights
Cover the flat with the humidity dome and place the flat under the under the lights. The lights should be about an inch above the humidity dome. Most seeds germinate well at normal room temperature, around 65-70 degrees F. Check each day to see if any seedlings have emerged. Once the seedlings are up, prop the humidity dome open for one day and then remove it completely. The lights should be kept around 2-3 inches over the tops of the plants.

Sources
You can get plastic liners, flats, growing media, humidity domes and many great seeds at Downtown Home and Garden in Ann Arbor. Altogether it seems like a pretty big investment – light fixture, chains, timer, flats, flat liners, humidity domes, seed starting mix. However, the light fixture, chains and timer will last a very long time, and the flats, liners and humidity domes will last can last 3 or more years if treat them carefully.