Seed Starting Season in Phoenix

Seed starting season never feels quite right in Phoenix.  As I write this, we just got .40" of our first winter rain of the season and the Christmas tree just went up over the weekend.  But, it's still time to start seeds for the spring season.  In fact, it's probably even a week or two late.  When it's time to start getting ready for the fall season it'll be July and you're sure to be more concerned about the 110+ degree temps going away than about getting some squash ready to plant in September.  

Nonetheless, it's time to start sorting through your seeds and thinking about what veggies seem like they'll be delicious in the late spring.  Luckily the process couldn't be easier.

Equipment needed:

Seeds
Seed starting mix
Planting containers (I use old cardboard egg cartons)
Seed starting tray
Nursery pots
UV grow lights, or a sunny windowsill
Wooden kebab skewer, or similar small poking instrument
Guide to growing vegetables in the desert (I like Southwest Fruit & Vegetable Gardening, and Extreme Gardening)

When to start your seeds:

Generally speaking, I put my seed-started plants in the ground outside in early February for the spring/summer season and in early-mid September for the fall/winter season.  I allot 6-8 weeks to give sufficient time for the seeds to sprout and the plants to become hardy enough to survive outdoors (some varieties might grow quicker or slower, so check your seed packets for possible adjustments).  That puts seed-starting time at early-mid December for the winter, and early-mid July for the fall.

What to do:

Before even planting seeds you should do some planning and organization.  

First, think about what veggies you'll want to eat and will actually use.  Then consult the guide or the internet to make sure you're going to plant them in the right season.  A lot of plants, like tomatoes and peppers and tomatillos can handle both spring and fall; others, like cilantro, won't tolerate heat and might not survive long enough to produce.  You'll also want to determine which plants should be started inside and which are direct-sow.

Once you have your planting list picked out and confirmed it's the right time of year, go get your seeds.  Your local nursery will have a supply of seeds appropriate for the location and can give you great planting tips; or find one of the many heirloom seed suppliers online to find interesting varieties.  

Now it's time to get planting.   An optional first step is to cut small holes in the bottom of each pod in your egg carton so that roots can escape easily once it's transplanted.  After that, I like to fill my planting containers with damp seed starting mix.  Putting the seeds into dry soil inevitably leads to them being splashed out of position when you water them for the first time, which is very frustrating after going to such effort to push tiny little seeds .25" into the soil and spaced apart from each other just a little bit.  

Drop 3-5 seeds in each pod of the egg carton and use your kebab skewer to push them into the soil the recommended distance.  Then use the skewer to lightly push soil back over the seed and repeat for everything you want to plant.  If you have leftover seeds, do yourself a favor and store separately seeds that start in the spring vs. the fall, and transplant vs. direct sow.

All that's left to do now is to put the egg cartons in the tray and put the tray under your grow lights.  Position the grow lights just a few inches above the seeds and incrementally raise them as the seedlings grow so they stay just a few inches above the tallest plant.  Seedlings naturally grow toward their light/energy source and keeping the grow light low will prevent them from wasting energy growing tall (leggy) toward the light and instead lets them use their energy to grow strong and healthy.  An easy way to do this is to make a chain of little carabineers so that when you need to adjust height you just remove a carabineer to raise the lights.   

Keep the soil moist according to the planting instructions for your plants.  I prefer to pour water into the tray and let the egg cartons and soil suck up moisture.  This, again, helps prevent dislodging the seeds from pouring water directly onto the soil.

Once the seedlings have grown several inches, transplant them into individual containers.  The egg carton pods can easily be cut apart so the entire pod can be placed in soil.  First, carefully tear apart a side or two of the pod so the roots have more places to grow out of...but roots will have grown into the pod so go slowly to avoid damaging them.  When transplanting has finished, return the seedlings to the grow lights until they can be permanently planted in the garden.  Let them spend the last few days before permanent planting outside, but not somewhere they will get direct sun, so they can adjust to climate changes from your house to the outdoors.