The moment just before the official start of summer is a good time to take stock of how spring went in the garden. Before I forget, I make notes on what worked and what didn’t — how there weren’t enough of that Primula over there, and too much of that Pulmonaria in another spot, or which patch of some overly enthusiastic ground cover I’m going to reduce or eliminate next.
There are always a few performance glitches to record and resolve, too, such as homegrown seedlings that didn’t meet expectations or perhaps spring-flowering bulbs like daffodils or tulips that didn’t perform as you had hoped.
Here are a few of the most common “what went wrong?” questions I get from gardeners every year, as spring fades.
I grew my own vegetable starts from seed, but my seedlings were tall and spindly compared to the ones at the garden center. Why?
Most of us lack a greenhouse, where those garden-center seedlings are grown, so we fall short on how much light we provide. Thomas Björkman, a crop physiologist at Cornell University who studies vegetable seedlings, told me years ago that, for home gardeners, the stretching of young plants is almost entirely because of insufficient light. Other factors — including temperature, improper use of fertilizers and even the spacing between seedlings — can also affect how a seedling grows, but it’s important to focus on increasing light so the tiny plants don’t reach for it to damaging effect.
Forget growing seedlings on windowsills. Even many light fixtures for plants that look very bright to our eyes output a small fraction of the measurable sunlight that a plant would soak up outdoors on a cloudy spring day, let alone a sunny one. And some lights gardeners use for seed-starting, like old-style fluorescent T12 tubes and even high-output T5 fluorescents, emit heat when placed close enough to plants to offer maximum light — another thing seedlings don’t like.
The newer, more efficient grow lamps, including LED bulbs, produce more light with less heat. I position a reflective hood fitted with T5 bulbs about five or six inches above the tops of the seedlings, adjusting the hood on pulleys as the plants grow, and run the lights about 14 hours a day. If I were to upgrade my setup, I’d choose a similar reflective hood, but with newer LED bulbs that are less expensive and more technically advanced.
My trick: Because at any time I have only a few flats going, on fair days warmer than 50 degrees I carry them outside to a bright but protected spot like my back porch. (Nothing beats the sun.) As they get acclimated to spending their days outdoors, I move them gradually into brighter exposures.
Another place you can go wrong in seed starting is with the heat mat, placed below seedling flats to encourage germination. It is called a germination mat because it is for use only then, to awaken the seed, and not once the seed has broken the soil surface. Likewise, the clear plastic dome on top of the flat — which simulates the germination chamber in a laboratory or commercial greenhouse — is intended only to create an extra-humid environment that will encourage the seed to break dormancy. Remove both at the first sign of life or risk weakening the baby plants.
What happened to the tulips I planted last year? So few bloomed, and some didn’t even sprout this year.
A search for the genus Tulipa will probably return words like “bulbous herbaceous perennial.” So it is a disappointment to many gardeners when tulips don’t reliably return, behaving instead like annuals.
A few things are at work, which could loosely be summarized as: Wrong tulips, wrong place.
The tall hybrids we love for their bold spring displays and for cutting are not tulips the way nature made them, but ones that have been highly bred. Plus, we are not gardening in the climate that the smaller wild species evolved in, including places like Turkey, with cold winters and hot, dry summers, where bulbs happily rest in dry ground. Summer rains (or irrigation of beds to water adjacent plants) make tulip bulbs unhappy.
At public gardens where displays of thousands of bulbs are often created to welcome visitors, the gardeners know this. They treat them like an annual, planting in the fall and pulling and discarding the spent bulbs after their show the next spring, then replanting the bed with the next annual for summer display.
Some tall hybrids can be coaxed into longer life if given a little extra attention. With deeper planting (down not just six inches but 10), the Darwin hybrids may behave more perennially. The bulbs are better insulated from summer moisture fluctuation at that depth and feel more at home.
After they bloom, remove the spent flowers as soon as they fade, but let the foliage remain to mature naturally, replenishing the bulb underground.
Bulb catalogs note which selections are best for “naturalizing” — meaning, they are inclined to stay awhile and even spread about in the best circumstances. With tulips, that designation is more likely to be given to the smaller species or botanical types, like Tulipa tarda, batalinii or clusiana.
One issue that may hamper the reliability of even those scaled-down choices: hungry animals. From deer down to chipmunks and even voles, many animals apparently regard tulips as a culinary treat.
My daffodil foliage is lush and healthy, so why do I have fewer flowers every year?
Not far from the roadside in the woods near my garden, I sometimes glimpse the distinctive sight of a mass of daffodil foliage in spring — but never any flowers. I know that is where a house or barn once stood, but is no longer. Narcissus are long-lived where they are happy, and naturalize well, even making more bulbs gradually underground. What they can’t do in certain conditions is bloom well.
Here are a few possible triggers for diminished bloom. (All of the advice that follows presumes that you started with a species or variety suited to your region.)
Not enough light: Full sun is preferred; light shade, tolerated. Fluctuating light patterns, as nearby shrubs and trees grow, can mean that daffodils planted in a sunny spot are now not getting the light they need for peak bloom. Judicious pruning may help, but sometimes (as with the bulbs I spied in the woods) the only thing that will is rescuing and replanting them in a sunnier spot. This is best done just after the foliage fades, by digging the whole clump and transplanting it. But the bulbs can take a year to settle in, so peak bloom may not happen right away.
Root competition for moisture and nutrients: Near trees and shrubs, another potential issue is root competition for essential resources. Moisture is required during weeks of active growth, from emergence in spring until the flowers and then foliage fade. The driest, shadiest spot of all, which in general does not suit bulbs, is under evergreen woody plants. But soil moisture in the other extreme can rot them, so good drainage is a consideration.
The foliage was prevented from ripening: Gardeners sometimes rush to tidy up the daffodil bed, tying up, braiding or even cutting back the strappy leaves. Cutting back foliage too quickly after bloom curtails the plant’s ability to photosynthesize and store energy in the bulb for next year’s show. A minimum of six weeks’ ripening time, left just as they are — open to the sunlight without any rubber bands or braids, please — is recommended after bloom. I let mine go until they are fully faded to tan, which takes until about the beginning of July, after the April and May flowers.
Too much nitrogen: Feeding with high-nitrogen fertilizer can diminish flowering in favor of foliage in most any plant, including Narcissus. Nitrogen is the first number in the N-P-K ratio on the package, and all-natural organic bulb foods might be labeled 3-5-3 or 3-5-4, for example. But according to the American Daffodil Society, not feeding at all can hurt, too, in case you skipped it for more than a year or two.