Clove (Syzygium aromaticum) cultivation

This is the first time I've ever tried to grow cloves, so take any advice here with a small Siberian salt mine. In fact, this post may point out some things not to do. If you are interested in growing clove trees, read on. If not, skip to the next blog.

I bought my clove seeds over the Internet directly from Seeds Hawaii Inc., but the company now sells on eBay (as of the date of this post). The minimum order is 50 seeds. I needed all of them.

I was told the first seeds matured in early November. (The season is short. Check the website for availability.) My seeds were shipped USPS Priority November 10 and arrived on November 13, within the three days you expect from Priority Mail. My mail is delivered to a metal box at the street usually just before 2:00 pm. I picked up the mail that day about 4:00 pm. The high temperature Nov. 13 was in the mid 40's (deg. F.). By the time I got the package open, I found more than half of the seeds had deteriorated.

Clove seeds don't have an outer seed coat. They consist of a pair of cotyledons and a radicle. This radicle, or embryonic root, appears to be the most tender part. Disturb it and the seed is a goner. More than half of the seeds were entirely chocolate brown upon arrival. More than half of the seeds with green cotyledons had a brown radicle. I believe all of these seeds were DOAs.

I bought a professional grade 22 inch by 22 inch heat mat and thermostat. I bought a Jiffy brand Seed Starter Greenhouse measuring about 11 by 21 inches. I filled the 50 peat pots with Miracle-Gro Seed Starting Potting Mix level with the top of each pot. I used my kitchen sink sprayer to moisten the potting mix with warm water. Our water is from a well and is quite hard, lots of lime. The soil surface was wet enough to clump together. I used a butter knife to make a depression in the surface and dropped each seed in, radicle down. I buried each seed with between a half and a quarter of the seed top showing. I sprayed the bed with more warm water to firm the seeds in place. I put the heat mat on the floor and the mini greenhouse squarely on one half of the mat. I mounted the thermostat probe level with the surface of the potting mix and set it on 82 deg. F. (I haven't checked this thermostat for accuracy with a thermometer yet.) I'd finished planting all 50 clove seeds, brown or green, before I went to bed on November 13.

I left the mini greenhouse mostly undisturbed for the next three weeks when I found three seeds had sprouted. Unfortunately, all or almost all of the brown seeds had grown a fuzzy white mold. At this point, I threw out all of the brown seeds. I kept eight bright green seeds (including the three sprouts) and three more that were mottled green. I could not see any mold growing on any of these seeds. I mounted a 25 Watt spiral fluorescent light directly above the three sprouts, touching the top of the greenhouse roof. I boosted the thermostat to 85 deg. F.

The three sprouts were entirely bright green. At first, all I could see was a pair of cotyledons on a root stalk. They had pushed a quarter inch or so above the soil surface and had spread apart like butterfly wings. A couple of times each day, I opened the greenhouse. (Like I could help myself!) The heat of the mat causes condensation to form on the clear roof of the greenhouse. If you flip it carefully, you can collect this condensation. I used the condensation water to moisten the soil around the sprouts and seeds as needed.

By December 13, no further seeds had sprouted. As far as I could tell, none of the eight seeds that had not sprouted were showing any signs of progress. I decided to examine them; I pulled them up. All but one had an entirely brown radicle, and the tip of that remaining radicle was brown. None of the brown seeds or the seeds with an entirely brown radicle ever developed any roots. The one seed with a brown tipped radicle had formed a second tiny root. There is a very slim chance I did not disturb this second root when I replanted it, so I guess it's possible I'll get one more sprout. I'm not holding my breath.

Then I examined the three seeds that had sprouted (visually--without uprooting them, of course!). One grew its stalk from the normal bud between the cotyledons. This stalk started off bright red. As it grew, the tip faded to orange and the stem turned green. On the other two, the central bud had been damaged and had turned brown. (I mean it--these things are tender!) On either side of this bud, in the crotch between the bud and cotyledon, tiny red nubs formed. These nubs developed into stalks over the next few days. One looks like it will have two stalks, the other just one. Developmentally, these two are far behind the one growing from the central bud.

What have I learned?

1. Pay extra for overnight shipping. Do not let the package linger in the cold for a second--sign for it if you must.

2. I won't bother planting seeds with solid brown radicles or cotyledons. They'll just get moldy.

3. I'll try not to use as much water to start with next time. Instead, I'll open the greenhouse for a daily misting until the soil seems moist enough. I'll use boiled and cooled rain water instead of well water.

4. I won't bury the seeds as deeply. I'll slice plenty of room for the radicle into the surface of the soil and gently, very gently, press the radicle end down, leaving most of the seed on top of the potting mix.
5. Leave the seeds alone for longer than a month. One more seed might need to regenerate its root and could sprout later. You never know.