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Tulips and Calcium


Yet another incarnation of the gorgeous ‘Apricot Beauty’, which I hope to bring back year after year.

I just discovered something that may keep my tulip bulbs coming back season after season, fat and full of flowers.

In his book Buried Treasures, Latvian bulb hunter/breeder Janis  Ruksans (this is not the proper spelling of his name; anyone know how to do special characters in WordPress?) mentions how he found only small bulbs one year when he was harvesting tulips. Tracking down the reason, he came to conclusion that soil pH was the problem.

The soil was acid, at 5.5 pH. While this wasn’t harmful to the daffodils he’d had in that field the year before, lack of calcium upsets tulip bulbs, so they make only tiny bulbs.

I’ve dug up a fair amount of tiny tulip bulbs myself, and wondered why I couldn’t breed them, since weather conditions are ideal in my area, and I thought I was giving them all the nutrients they needed. This was interesting news.

“A few years earlier I had applied lime to all of my fields, but the following years were rainy, and calcium is one of the elements that quickly wash out of the soil,” Ruksans says.

In my area, the soil is acid. Real Gardeners I’ve known (and even I) have put lime in the soil to make it more neutral, but my understanding was that it takes awhile to be effective. That could be faulty understanding on my part, or maybe calciium is more persistent in our soil than Ruksans’s. (Local soil is usually clay and granite, so it holds everything.)

On the other hand, the soil I plant most of my bulbs in is potting soil, which is light and fluffy. Calcium probably leaches out of it every time it rains.   And the fertilizers I use have some calcium in them, but not a lot. One way or another, it could well be that my tulips need calcium.

Actually, all plants need calcium. More than a lot of us think.

Earlier this year, my lilies had buds that  shriveled and turned brown, never producing a flower. This has always happened to one or two of my lilies, but this year, it happened to a lot of them. I started trying to figure out why.

My Spray-N-Grow catalogue said that their foliar calcium spray makes plants more resistant to disease, prevents blossom end rot, and helps them recover from stress. It’s also something they need to grow properly.

My Peaceful Valley catalogue recommended foliar calcium sprays for higher yields (30-50%, depending which university study you’re reading). Some of their customers reported Brix readings tri;pled with the foliar calcium spray.

Brix is the sugar content in plants, and when you raise the Brix, you increase flowering and fruiting.

So all in all, foliar calcium seemed like a good idea. Since I was putting it on my lilies, I decided I might as well put it on my whole garden. Both catalogues suggest spraying every 2 to 4 weeks. I admit I didn’t quite keep up on that schedule–I already do two kinds of general vitamin/fertilizing sprays, both of which are not supposed to be used with anything else, and sometimes I just don’t have it in me to spray again that week. (By the way, Ruksans is also big in favor of foliar sprays; he says it’s made a huge difference in his nursery.)

The foliar calcium spray Peaceful Valley carries is quite expensive, but you don’t need much of it–one teaspoon of dried calcium salts for a gallon of water. I’m lucky to have a local store that has an open jar of the salts and sells them in bulk, if that’s the word: I bought about two tablespoons’ worth and I still have some left.

I don’t know for sure if this increased my yields or flowering. There are way too many variables, including deer. But I’m willing to keep it up, especially if it means my all my lilies will flower every year. It just seems like a good idea generally. It seems plants need calcium as much as we do.

And if calcium can keep my tulip bulbs from going tiny and disappearing, I’m for it.

So here’s my plan: this fall, all my tulips–heck, all my bulbs, why not–will get an extra dose of calcium in the soil mix. And when the first leaves poke up (which is time to start fertilizing anyway), I will give those bulbs a foliar spray with calcium.

That won’t affect my flowers this year: bulbs have a flower already formed inside them from last year. But it will affect the future of my bulbs.

And if it means I don’t have to re-buy my longtime favorites, like ‘Apricot Beauty’ and ‘Queen of the Night’, then it will also affect my bank balance. Positively.


Janis Ruksans, Buried Treasures: Finding and Growing the World’s Choicest Bulbs, Timber Press, 2007, pg. 45. This is a great book, much of which is devoted to bulbs growing in their native areas. Ruksans climbed mountains and forded lakes, hunting bulbs. Much can be learn about where species bulbs come from, and their many variations (most of which we don’t see on the bulb market). Ruksans is also a  minute observer of how these bulbs and their seeds behaved when he got them home to his nursery.  (I apologize for not giving the author his proper diacritics; I haven’t found a way to do this online. Suggestions welcome.)

Spray-N-Grow catalogue, summer 2008

Peaceful Valley Farm & Garden Supply 2008 main catalogue, pg. 96

{ 1 comment… add one }

  • Paul Z October 13, 2014, 11:39 am

    characters? paste ’em from Word
    may not be right, but works

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