Friday, March 22, 2019

Compost vs. N-P-K (Nitrogen, Phosphorus, and Potassium)

Have you ever wondered what the three numbers on the front of your fertilizer box stands for?  5-5-5, or 2.5-5-3?  

The first letter is for nitrogen, the second for phosphorus, and the third for potassium.  The numbers tell you what percentage of each element is available per bag/box.  5-5-5 means 5% N, P, and K.  2.5-5-3 means 2.5% N, 5% P, and 3% K. These letters and numbers matter because different plants have different nutrient needs.

Compost is NOT plant food and often does not supply adequate N, P, K. It is a great amendment and will increase your organic matter.  Its addition will make your soil more friable and help it hold more moisture, but it does not feed your plants.  Even if you have great tilth in your soil, you will still need to consider the nutrient needs of your plants. 

1.  To start fresh, get a soil test.  Here is a link to a local resource. Most of the plots at Marymoor are fertile but a soil test is the only way to be sure.  pH is also a need to know number.

2.  Know what you grow.  Most garden plants do well in the PNW, as a majority of garden crops like an ~6.0-7.0 pH. However, not all plants need the same amounts of N, P, K.  Some crops are heavy feeders and do best when fed during the growing season, examples are corn and tomatoes.  On a side note, know what type of watering schedule your plants need as well, their needs can be very individualized.

3.  General N, P, K rules.  A fertilizer with a higher N number will support leafy growth. (Did you know when you eat onions,  you are eating leaves?)  A fertilizer with a higher P number supports bulbs and blooms and therefore fruit.  The last number, K, supports cell growth and all around plant health.

4.  More is not better.  Too much organic matter as well as fertilizer is not helpful and can be harmful to your plants.  Follow fertilizer application directions and when in doubt, do a soil test.

We hope you have a successful start to the garden season.  If you have questions, please ask at



Monday, March 11, 2019

March Garden Chores

     March 20th is the official first day of Spring.  We did have a day of snow in March but hopefully, the snow is not making another appearance. Warm days are here to stay and if we collectively say it loud enough, it will be so.

     1. March is the perfect time to finalize seed orders.  Some highly sought after seed and varieties may sell out quickly. Get those seed packets in your hands ASAP. 

     2. It's time to buy bare root plants and canes.  The soil is no longer frozen so get those babies in the ground.  Leaving them in their packing material or in plastic bags can encourage them to dry out or rot.  (Examples are asparagus and berries.)

     3.  If your garlic is coming up, it may be time to thin your mulch or top dressing so those emerging greens can get some light.

    4.  Lay some cardboard out or overturned melons.  Slugs might find a home underneath and then you can dispose of them.

     5.  Keep cleaning up your garden.  Removing debris can help control pests and improve the sanitation of your entire garden.

     6.  Take soft and hardwood cuttings of plants you want to propagate like currants.

     7.  Time to start warm weather plants like basil and tomatoes.

When you are out at the garden again take a nice inventory of your garden spaces and plan for the upcoming season.  Remember to rotate crops as much as possible.  See you out there.