Seattle Garden Calendar: April

1. Plant a tree in honor of National Arbor Day, which is April 30.

2. Give your lawn a face-lift by aerating, overdressing and topdressing about every two years. (Read more about how to do so in this blog post). Otherwise fertilize your lawn with a good organic slow-release fertilizer.

3. Mow weekly, removing no more than 1/3 of the blade.

4. Add compost to your vegetables, trees, landscape beds.

5. In the vegetable garden, continue to plant cool season crops, such as lettuce, beets, snap peas, chard, radish, spinach and parsnip.

6. Plant seeds for annuals such as cosmos, asters, marigolds and zinnias.