Editor's Note: We're excited to have Hilary Dahl, co-owner of the Seattle Urban Farm Co., and creator and Host of the Encyclopedia Botanica Podcast, as a guest blogger. In this post, she's offering great advice on planning and prepping your edible garden. Whether you are brand new to edible gardening or a seasoned pro, you'll find great tips to make this year your best vegetable harvest ever!
Author's Note: To keep things simple, this blog is focused on annual vegetable crops. An annual crop is one that is replanted every year, which includes most of the things people think of as vegetable crops (i.e Tomatoes, Cucumbers, Lettuce, Carrots, Beets). This is in comparison to perennial crops, that live year after year (i.e Apple Trees, Blueberry Bushes, Raspberries). I think it’s helpful to separate them into those categories because the annual crops have some pretty specific requirements.
A quick overview of garden planning basics
Almost all annual vegetable crops require a minimum of 6 hours of sunlight during the growing season to thrive. And in our region, more sunlight is always better, so if crops can get 10 or 12 hours of sunlight during the summer, that is even better.
Consider seasonal sunlight.Because of the high latitude of Seattle, the sun sits much lower in the sky in the winter months than it does in the summer months. This means that areas that don’t appear to get much sun in the winter might receive plenty of sun in the summer. On the flip side of that, deciduous trees can throw people off when picking out a site in the winter. It might appear that a site will receive full sun, but when the tree fills back out in the spring, the site might be completely shaded.
It’s also important to keep in mind that the sunniest spot isn’t necessarily on the south part of your yard. For example, my garden is actually on the north side of my property because it has full southern and western exposure.
There’s a great phone app called Sun Seeker that can show the solar path, its hour intervals, its winter and summer solstice paths, rise and set times, and more from anywhere on your site.
Size & Accessibility
Your garden is more likely to succeed if you see it every day. If possible, I highly recommend to gardeners to spend 15-20 minutes in the garden a few times a week, rather than a few hours every couple of weeks. This allows you to find pest and disease issues before they get out of hand and to make sure that you can tend to any other issues as soon as they happen. Having a garden that is easy to get to will help make frequent garden visits possible.
Once you find the right spot, create a dedicated space, set aside just for your annual vegetable garden. This will allow you to care for the soil in a way that is helpful to annual plants and would be harmful to many perennial plants. Consider the garden size that is most appropriate for you: how much time do you want to spend in your garden each week? Generally, a 100-400 square foot garden can be managed in 1-2 hours per week IF you’re not hand watering...
Think about where all of your water sources are on your site and how you’re going to get water from them to your garden. It is possible to hand water a garden, but it takes a lot of time. In order to have a really successful garden, it’s going to need to get a lot of water.
Keep in mind that we actually experience somewhat of a drought here in the Seattle area during most summers (occasionally going 90+ days without rain), so you may want to consider installing drip irrigation that is hooked up to an automatic timer so that you don’t have to spend all of the time you’ve allotted to your garden just watering every day. Automated drip systems on a timer are the simplest way to manage the irrigation in the annual beds. This can be attached right to the hose bib on the side of our house, and irrigation can be run from there.
Prepping your soil
When creating a garden it’s important to keep in mind that the health of your plants depends on the health of your soil. With proper care (aka, the following steps), your garden soil and plant health should improve with time.
Initial Soil Quality
Test your soil before you build a garden if you think there could be lead in the soil. It’s not super common, but we do find contaminated soil from time to time. King County offers soil tests for free. If you’re not in King County, we recommend the UMass Amherst soil test.
Test your pH
The pH of your soil affects the availability of nutrients to your plants. This means that even if you have added compost and fertilize your garden soil with everything imaginable if the pH is way off, the plants will not actually be able to absorb and use these nutrients.
You have three basic options for testing your soil pH. You can use a pH testing kit at home or you can send a soil sample to a lab. Both of these are good solutions, but I think for the average home gardener a home test is sufficient.
For almost all annual vegetable crops a pH between 6.2 and 6.9 is ideal. If your pH is above 6.9, it is considered overly-alkaline may benefit from a soil acidifier such as elemental sulfur. If your pH is below 6.2, it is considered acidic and will require an application of Calcitic lime or Dolomitic lime to make your soil more basic. In general, PNW soil is more likely to be overly acidic rather than overly basic.
There’s never a bad time to add lime to your soil. Ideally, you’ll add it in the fall so it has time to adjust your soil, but if you have acidic soil, add it now and it will start interacting with the soil over the next few months so by spring it will have started to adjust your pH.
The advantage of Dolomitic lime is that it also provides magnesium and calcium to your soil, both essential plant nutrients. However, if applying Dolomitic lime, you'll need to be careful because over-application or too-frequent applications can throw the calcium-magnesium balance out of whack, which can lead to all sorts of plant health issues. If you haven’t performed a soil test specifically to get your current nutrient levels, it’s safer to add Calcitic Lime.
Organic matter is the backbone of healthy garden soil. Broken down organic matter gives your soil the loose, crumbly structure that plants love, helps the soil absorb water and hold it so the plants can soak it up, and supplies important nutrients that crops need to grow.
Adding 2-3 inches of compost once a year is sufficient if it is added in the fall. If you're adding compost in the spring, you'll also want to top your beds with compost in the fall to protect the soil structure during the rainy winter months.
Also, loosen and fork the soil in your garden every spring and fall!
We recommend that every vegetable gardener have one of each of the following:
Balanced organic granular fertilizer to add to the soil at planting time
Liquid organic fertilizer to foliar feed plants every 2-3 weeks. We used a kelp-based liquid fertilizer because it provides micronutrients.
Planning your crops
Direct-Seeding vs. Transplanting
Some crops prefer to be directly seeded into your garden rather than started in pots and transplanted. Some of these include carrots, radishes, turnips, lettuce mix, arugula, and beets (but these can also be transplanted). Other crops are difficult to grow directly from seed in the garden and will perform better if transplanted, either using purchased starts (baby plants) or by starting your plants from seed indoors and then transplanting into the garden.
For many people, especially beginners, I highly recommend buying starts. Growing your own takes some specialty equipment, dedicated space in your house and attention for several months. Often, growing out transplants on a windowsill without lighting and proper care will result in leggy (because they don’t get enough light), unhealthy transplants that will struggle in the garden. It’s often a better use of time and resources to buy starts to plant each spring.
Tips for Buying Starts
You can buy starts at the nursery to transplant directly into the garden. Nursery growers have to overseed each cell in a container to make sure none are empty, but usually, several come up and young plants can be separated and grown individually when transplanting. This is VERY important or transplanted crops will be stressed, overcrowded and stunted.
Some plants - squash in particular - don’t like to have their roots disturbed. It will shock them and slow their growth, so clip off all but one plant with scissors so they won't be overcrowded and stunted in the garden.
There are several different considerations to think about when laying out your crops. I've dedicated an episode of my gardening podcast, Encyclopedia Botanica, to each of these more in-depth planning topics, so check them out for more info. Follow the links below and you can play the episodes straight from my blog, no podcast player needed.
More information on everything discussed in this blog can be found in our instructional gardening books, Food Grown Right in Your Backyard, and High Yield Vegetable Gardening. These books are both available at Swansons!