Tuesday’s Tips — When to Plant Vegetable Seeds

Ah gardening! It’s all so simple, and yet it can get so freaking complicated, so quickly. Planting seeds for instance. The simple question is, “When can I plant seeds?” And the answer is…well, there are many answers depending on many factors, but let’s try to make it simple.

The simple story about seeds is they need the right soil temperature, the right exposure to light, and the right amount of water to germinate. Sounds easy and it is, kind of. If you follow some basic guidelines you’ll get a pretty good germination rate, not 100%, but good enough.

Here’s where we can make it complicated. This chart that shows the “practical” soil temperature for planting seeds to get a good crop versus the “optimal” temperature for seed germination.


From Gardener's Supply Company

I found it very interesting that the optimal soil temperature where you can expect almost all the seeds to germinate for corn or cucumbers would be 95 degrees. Really! My soil never gets that warm and I’m betting yours never does either. So ignore the optimal temperature and focus on the practical temperature.

Now the next question could be how in the heck do I know what my soil temperature is? And the answer is that there are a couple of ways to do that. One would be to get a soil thermometer to test your soil (a little complicated), or you might go to your local extension’s website and find a record of soil temps (still a little complicated). Or you could say, “It’s late March/early April in Zone 10 (when, generally speaking, the soil temps should be good) and that means it’s time to plant.”

Now I’m not saying you shouldn’t pay attention to your soil temperatures. (In fact, if you regularly have trouble with a particular crop seed, this might help you figure out where you’re going wrong.) It’s just that you don’t have to be so precise.

A good rule of thumb is to plant warm season crops when the soil temps are between 50 degrees and 60 degrees and the daytime/air temperature is between 65 degrees and 80 degrees.

Most of the veggies on the following list are warm season crops, but a few are cool season crops that need a long time to grow before they are mature. Still others can be grown all year round in our zone. But let’s just make it as simple as possible to avoid further confusing anyone. Here’s your list of vegetable seeds to plant right now in coastal Southern California (USDA Zone 10/Sunset Zone 22, 23, 24) in late March/early April.

Seeds to plant in March/April

  • Beets
  • Bush Beans
  • Cabbage
  • Cantaloupe
  • Carrots
  • Chives
  • Collards
  • Corn
  • Cucumber
  • Eggplant
  • Endive
  • Jicama
  • Kale
  • Kohlrabi
  • Leaf Lettuce
  • Lima Beans
  • Okra
  • Parsley
  • Peppers
  • Potatoes
  • Pumpkin
  • Radish
  • Snap Beans
  • Spinach
  • Swiss chard
  • Summer Squash
  • Tomato
  • Turnip
  • Watermelon
  • Winter Squash

Planting tips:

  • Nothing short of full sun is going to cut it for most plants. Make sure you place your veggie garden where it will get at least 8 hours of sunlight.
  • If you have heavy clay soil, do yourself a huge favor and build a raised bed. The truth is that unless you have perfectly loamy soil, you will have much better results with a raised bed.
  • Raised beds are absolutely the way to go if you are in an urban area where your soil is likely to be contaminated with lead and other pollutants.
  • If you have gophers, nail 1/8″ – 1/4″ hardware cloth on the bottom of your raised bed frames to keep them out.
  • Use topsoil in your raised beds, NOT potting soil.
  • Amend with a good organic amendment.
  • Keep you seeds evenly moist until they sprout – use a hose sprayer or a sprinkler.
  • Install drip lines. Ditto on the success factor with drip watering for vegetables, plus it will conserve water.
  • Mulch, mulch, mulch. Conserves water, keeps soil temperatures moderated and plants happy (i.e. not stressed), and cuts way down on weeds.

This is a link to an awesome UC ANR chart that shows when to plant vegetables in all California regions, how to plant them, how much to plant for a family of 4, and how to preserve your crops.

Folks in cooler planting zones should be starting seeds indoors for planting when the air and soil temps warm up. For Durango and all other zones — find out from your local extension or nursery when the soil temps will be 50 – 60 degrees and plan on getting seeds or seedlings in the ground then.

Mary Beth will be writing about Durango area planting in the coming weeks.


Good planting.

One thought on “Tuesday’s Tips — When to Plant Vegetable Seeds

Add yours

  1. Thanks for the great tips! I haven’t had great luck with veggie gardening yet (lazy waterer that I am), but I’m feeling optimistic this year and creating a couple of raised beds. This information will be useful. Cheers!

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