Thursday, February 29, 2024

DIY Indoor Seed Starting - Part 1

Hey there! Last year I started my seeds for my garden outside after my last frost date - read that post HERE. I had a lot of success last year, but I also had a lot of flowers that ran out of time and didn't get to bloom because I didn't start the seeds early enough. In Michigan, our growing season is shorter, with our last frost date in May and first frost date in October. You can find your first and last frost dates by your zip code HERE. This year, I'm starting most of my seeds inside in hopes of more flowers!

I started out with the same seed starting trays that I bought last year. I just cleaned them really good with a peroxide disinfecting spray and warm water in my bathtub, since it's a frozen tundra outside!

I also cleaned my plant labels that I saved from last year. I like THESE plant labels because they fit underneath the humidity dome perfectly and they come with a marker.

Once everything was clean, I prepped my soil per the instructions on the bag, just like last year - add soil to a bowl and add enough water for the soil to be damp. Then I went through all my seeds and took out the ones that said to start indoors 10-12 weeks before my last frost date in one pile and another pile for ones that said 8-10 weeks before my last frost date. I stored my seeds from last year in half gallon mason jars with a bit of rice at the bottom to absorb any moisture and keep the seeds fresh!

I followed the instructions on each seed packet for seed depth and planted all my seeds in my 10-12 weeks before last frost pile. I planted 2-3 seeds per cell in my seed starting tray and added about a 1/2" of water to the bottom tray. 

I purchased THIS heat mat to go under my seed starting tray, since most seeds have the best chance of germination between 75-80 degrees and this is an unheated room in my basement.  I also lower the light down each time I am done working underneath it - I used a piece of wire between the chains to easily move it up and down by just folding the wire. I used a smart plug for my shop light to set a timer for the light to be on for 16 hours per day, but left the heat mat on nonstop.

A couple days later, I had some seeds germinating already! I checked the water level every couple of days and added more when necessary. 

I had added some zinnia seeds to a new seed starting tray a couple days after I started all of my 10-12 week seeds to have some super early flowers and they grew very quickly, so I needed to pot them up.

I ordered THESE 2.5" pots to plant my seedlings up in when they are too tall for the humidity dome or when they have multiple sets of leaves. These 2.5" pots fit in the bottom trays that came with my seed starting kit perfectly without wasting space. I eyeballed about 80% potting soil and 20% seed starting mix when I potted up the seedlings to the 2.5” pots.

I bought THIS little seed starting tool set that came in handy to scoop fragile seedlings out of the cell tray, but I used a butter knife last year that worked just as good! Once I scooped the seedlings out, I just carefully separated them and planted each of them in separate 2.5" pots. 

I used another heat mat that I left on nonstop for the plants in the 2.5" pots at first, but it seemed like some of the seedlings were getting kind of leggy, so I ended up removing the heat mat under the tray with the 2.5” pots and only used it on the tray with the humidity dome. After another few days, most of the potted up seedlings had started to develop their true leaves (second set of leaves), so I put a small fan on the table to run on low. This is our stroller fan, so it's very gentle and the battery only lasts a couple of hours. I have just been running it daily until it the battery dies. The fan mimics the wind and will toughen up the seedlings so they will be ready to plant outside. 

I ended up having to add another light to my table since I’ve had to pot up so many more seedlings. I have room under the lights for one more tray and then I’ll have to find a new table! I will keep checking the water and potting seedlings up when they are big enough and keep sowing the next round of seeds until we are closer to my last frost date and can sow seeds directly outside. After my last frost date, I will harden off the seedlings before I plant them outside, which I will do another post on, so be sure to check back for part 2!

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