Posts Tagged ‘mulch’


When I woke up on Sunday my plants were sparkly from frost, which means it’s bulb planting time. Actually, I would have been happy to plant bulbs two weeks ago, but ordering bulbs online means that you plant according the mail order shipping schedules, and bulbs arrive in Seattle in early November.

For daffodils and crocuses, which look best planted in large numbers, my go-to company is Van Engelen. At Van Engelen, I got 100 Narcissus jonquilla simplex bulbs (cute fragrant daffodils) for about $24. For smaller quantities of more special bulbs, I’m a big fan of Old House Gardens, which specializes in antique and heirloom bulbs. I have nothing against newer varieties of bulbs, but the Old House Gardens catalog has such exuberant descriptions and excellent customer service that I can’t help but try a few of their offerings. Fair warning- if you’re a plant impulse buyer, looking at the Old House gardens catalog can be dangerous for your gardening budget.

When gardeners talk about bulbs, we’re often grouping together a bunch of different plant structures including true bulbs, corms, tubers, and rhizomes. From a planting perspective, I find it less useful to focus on what “type” of bulb I’m putting in the ground than other factors such as how deep to plant and how long a bulb can be out of the ground. For example, both daffodil and crocus bulbs can sit on a store display for a month or two without damage, as long as they’re not exposed to heat, freezing temperatures, or sunlight. Lily bulbs, however, dry out quickly, and I don’t trust lily bulbs that have been in bags in the basement of Fred Meyer for who-knows-how-long.

I prefer to plant my bulbs using a small trowel or hori-hori, rather than a tool specifically for bulb planting, mostly because I try to avoid buying single-purpose tools, unless you can’t do the job without them. I like the trowel or hori-hori because you can plant the bulb without disturbing the soil too much, which prevents dirt with weed seeds from spraying everywhere. To plant the bulbs, I stick the blade into the soil, lever it forward, drop the bulb in, and slide the blade out. For bulbs that need to be planted deeper than the hori-hori blade, such as most lily bulbs, I have to pull out a bigger shovel. The bigger shovel always sprays some soil, so I put about a half inch of mulch down to stop any exposed weed seeds from sprouting. I only use thicker mulch if I’m using it to protect the bulbs from frost, and plan to gently remove some of the mulch in the spring, so that the shoots don’t have trouble punching through thick, heavy mulch.

Some gardeners like to put fertilizer in the planting hole, and some like to fertilize in the spring, and other gardeners will fertilize any chance they get. I’ll admit that I don’t fertilize my bulbs at all, at least not with stuff that comes out of a box. My garden isn’t a farm, and doesn’t need to be fertilized like one. The previous owners of my house didn’t just leave me with lots of weeds, they also left me with decent soil (minus all the weed seeds). I top-dress most of my planting areas with a thin layer of lightweight mulch, like Gardner & Bloom Soil-building compost, just to keep the weed seeds from sprouting, which has the side benefit of providing my soil with plenty of nutrients.

Here are the bulbs that are new to my garden this year from Old House Gardens:

And from Van Engelen:


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Fall garden chores

I’m already getting a crunchy layer of leaves on my lawn, mostly from my katsura tree. My hawthorn trees won’t be far behind. Luckily, my gorgeous japanese maple tree will probably keep its leaves until Thanksgiving. With our early snow last year, I got to enjoy the sight of pretty red leaves fluttering down to rest on a blanket of snow.

Seattle generally enjoys summery weather through September, but trees primarily use the length of daylight to determine when to begin winter dormancy, which is why my katsura tree is losing its leaves already. With that reminder that fall is almost upon us, what’s on my list to get done in the garden?

  • Start any remaining fall and winter crops. Now is the time to sow mache, miner’s lettuce, bok choy, and overwintering peas. I sowed my fall lettuce about a month ago, and tried a first sowing of winter lettuce two weeks ago. It can be hard to get lettuce to germinate evenly in this hot, sunny weather, so I’ll keep sowing lettuce for the next two weeks, to make sure I’m not left with bare spots in my winter lettuce beds. If the weather cooperates, I’ll also get a fall batch of cilantro from sowing some seeds now. If you want to grow overwintering broccoli or cauliflower it’s too late to start seeds, but not too late to buy seedlings.
  • Order bulbs immediately. It’s not yet bulb planting time in Seattle, but you’ll miss out on the best selection if you don’t shop early. Good mail order sites won’t send you bulbs until it’s the right time to plant in your region. In a few weeks, it will be time to plant not only tulip and daffodil bulbs, but also garlic and overwintering onions. I’m excited to grow egyptian walking onions for the first time this year. Remember that garlic and onions planted in the fall won’t be ready until early to mid-summer, so don’t put them in a spot that you’ll want to grow spring peas or even tomatoes. Bush beans are a good succession planting for garlic, or an early-sown fall or winter crop such as chard or sprouting broccoli.
  • Rake up those leaves. Grass and other groundcover plants will weaken or die if they’re covered by a layer of dead leaves for too long. Dead leaves make a nice mulch in areas with lots of bare ground during the winter, and can be left in place or raked off and put into the compost pile in the spring. Some people dig them into the ground in the spring, but digging is hard work and exposes new weed seeds, so I’m not big fan of that method, especially in ornamental beds. Using leaves as mulch does provide good winter slug habitat, so if you have particularly slug-prone plants, like hostas, bark mulch or wood chips may be a better idea in those areas.
  • Get any plants still languishing in nursery pots into the ground. Roots in pots aren’t nearly as well insulated as those in the ground, especially in small pots. Last year I put off planting some of my fall plant sale purchases, and our early freeze killed many of the plants still in nursery pots. Fall plants sales are only good deals if the plants make it through the winter. If you won’t have the time or space to plant it this fall or winter, don’t buy it. Also don’t make the mistake of putting pots against the walls of your house to shelter them, if you have overhanging eaves. It’s unlikely that you’ll remember to water them all winter.
  • Keep pulling up weeds, especially any that have flowers or seeds on them. Just remember the mantra, “This year’s seeds, next year’s weeds.” If the weeds have seed heads, don’t use them to create your own compost- throw them in the city compost bins. Home compost bins in the northwest don’t generally heat up enough to kill weed seeds.
  • There are lots of other chores that could be done this time of year, but could be put off until spring, like cleaning up tired looking plants. Maybe it’s better to just get out there and enjoy the garden instead of doing those chores. This the time of year when you can browse on cherry tomatoes while wandering around the garden spying on bumble bees and checking under big leaves for ripening pumpkins. If you can’t sit down in your garden without thinking of all the things you ought to be doing, get out and enjoy one of the public gardens around, or if you have a friend with a lovely garden, invite yourself over for happy hour on their patio. Sometimes it’s more important to smell the lilies than to turn the compost.

Japanese maple leaves make a pretty mulch for raised beds

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Mulching with pine needles

I’ve been spending my rainy winter days making a master plan for my garden, and I’m hoping to get some more fruit in there, since a small handful of berries lights up Brian’s face in a way that a whole wheelbarrow full of chard and onions never will. Because of this, blueberry bushes have been popping up all over the place in my garden plan. Advice abounds telling me to put blueberries in acidic soil, and how I can easily change the pH of my soil by mulching with pine needles. Since I have to rake pine needles off my deck anyhow, mulching with pine needles sounded great- but then I started reading about how the claims of pine needles changing soil pH were untrue.

Before I get to the shocking conclusion about the effects of mulching with pine needles, let me quickly remind you what the pH scale is all about. A pH less than 7 is acidic, and a pH more than 7 is more alkaline, which is also sometimes called basic. From a chemistry perspective, pH all adds up to which ions the soil has an excess of, especially the ions that add up to water, H+ and OH (it’s not just a coincidence that the letters add up to H2O). Don’t remember what an ion is? Ions are charged particles, and when it comes to soil science, ions are usually the product of dissolving something in water. Some essential plant nutrients are present in damp soil as ions, including calcium, magnesium, and potassium.

A few of the things that effect native soil acidity are heavy rainfall, the parent material of the soil, and the amount of decaying organic matter. While those factors add up to generally acidic soil in Western Washington, who knows how much of the dirt I’m gardening with was naturally deposited on my little plot of land and how much was hauled in.

So do studies show that mulching with pine needles increase acidity? It depends on which study. Some folks have seen slight decreases in pH (which means increases in acidity), and others haven’t seen any pH effects. Does this mean that some of the studies must be wrong? Of course not- whether a mulch or soil additive will change the pH of a soil depends on lots of factors, including the amount of rainfall in the area and especially the composition of the soil. Some soils have more buffer capacity, which means that they are more able to resist changes in pH. Clay soils are known for their ability to resist pH changes, as opposed to sandy soils.

Am I going to put those pine needles that I raked off my deck around my blueberry bushes?  You bet I am. My pine needle mulch may not make the soil acidic enough to keep my blueberry bushes happy, but at least it will help smother the weeds.


[1] M.L. Duryea, R.J. English, and L.A. Hermansen, “A comparison of landscape mulches: Chemical, allelopathic, and decomposition properties,” Journal of Arboriculture, vol. 25, 1999, p. 88–97.

[2]Raising Soil pH and Soil Acidification

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