Seed Starting 101
Tootie & Dotes +Resident Green Thumb & Contributor: Amanda Eastvold -
Why Should I Start Seeds? It’s April here in the Northland, but don’t let this warm weather fool you. The temperatures can and WILL fluctuate and nightly freezing is still happening throughout most of the state. (It’s actually snowing as I write this). While we northern gardeners are busy dreaming of dirt, gathering supplies and planning our plots, we are mostly just waiting. Waiting and waiting. Waiting for our seeds to arrive in the mail and waiting for the ground to thaw.
The good news is, you don’t have to wait any longer to get your garden on! The end of March and beginning of April is the perfect time to start your seeds indoors. No matter how many times I start seeds, I never tire of this yearly ritual. It pleases me to no end to transform my kitchen into a mini-greenhouse for an afternoon and then watch my little babies growing happily on a sunny shelf. I just love to get my hands dirty once again and to smell that soil and to... oh, I’m sorry, where was I? Oh right! If you’d like to try your hand at starting seeds, or have tried it before with less than stellar results, I’m here to tell you: YOU CAN DO IT.
It can be a real drag to live in Zone 4, but we love our home state and I won’t trash talk her. Here in Minnesota, we straddle Zones 3 and 4 according the plant hardiness zone map. This means our growing season extends from mid May (last frost date) to mid September (first frost date). That means we need to give tender plants and plants that require a longer growing season a head start. But let’s get right down to it.
Containers: Seed trays or pots and covers Labels Squirt bottle or small nozzled watering can Sunny window (south or southwest facing) Soil: Seed Starting Mix (do not attempt to use soil from your garden) Seeds!
There are lots of choices here. If you’re a first timer, keep it simple and use individual pots. You can use round plastic pots or peat pots (the fiber-looking ones). Peat pots are great for all types of seeds and are planted out directly into the ground so you don’t have to worry about disturbing the root system. While some people might steer you towards them, do not use egg cartons. These are too shallow for healthy root growth and wick moisture away from the soil rapidly. Peat pots can come individually or in 6 packs, either work nicely. I suggest placing any pots you use into a seed tray to allow drainage that won’t damage your surface.
If you’d like to plant more seeds per surface area, or you have limited space indoors, you might consider getting seed trays. These are long, flat, black plastic trays that can be fitted with clear plastic covers. In a seed tray, you can plant many more seeds. I find it easier to work with trays because they take up less space; I can keep the soil more evenly moist and I use less soil overall. The only drawback is that you may have to repot the seedlings into bigger pots as they grow.
If you’re using the tray method, a soil blocker can be a good investment. This compacts and shapes the planting medium into nice square cubes, allowing you to plant seeds individually into each block. If you’re just starting out, don’t worry about this step. If you don’t have a soil blocker, a small spatula can help you “cut” the soil into cubes or blocks.
No matter what type of container you choose, make sure they are clean. If you are reusing old plastic pots or seed trays, make sure to clean them with warm soapy water, then disinfect them with a water and bleach solution to get rid of any bacteria that could infect the seed or soil.
While you don’t technically need them, clear plastic seed tray covers trap heat and moisture so the seedlings stay warmer and dry out less quickly. I recommend these. Saran wrap can also be used, but if you’re purchasing seed trays, just go ahead and get the covers too. The plastic covers also serve to keep tiny hands from looking for treasures in the soil (that has happened more times than I can count). Once the seedlings start to emerge, you will remove the cover.
SOIL / PLANTING MEDIA
Make sure to get seed starting mix, and DO NOT use soil from your garden! Seed starting mix doesn’t have any actual “soil” in it at all. It is usually a mix of vermiculite and peat, and can contain other organic matter such as worm castings. Buy organic whenever possible. Commercial seed starting mix is sterile and is finer and lighter than regular potting soil and will hold moisture longer.
Step 1: Prepare your Potting Mix
Mix the seed starting mixture with water in a large plastic tub. This gets the “soil” evenly moist and you won’t have to worry about it settling in the pots. Mixture should be moist and can be shaped easily into a ball, however, it should not be saturated. You should not be able to squeeze excess water out of the ball. If you’ve added too much water, simply add more potting mix and vice versa.
Step 2: Fill Pots or Trays
Fill your pots and/or trays with this mixture. Tap the pots or tray on the table or floor as you fill it to help the mixture settle. You can press it gently with your hands, but do not pack it super tight; you just don’t want air pockets in the soil. If you are using a tray and don’t have a soil blocker, you can use a tool to “cut” the soil into cubes to hold individual seeds. These cubes will basically be their own self-contained pot. This is a good test to see if your soil is moist enough. The cubes should not crumble when cut. If they do, dump it back in the bin and add more water.
Step 3: Add Seeds
I use a pencil to make a small hole for the seed to go in. They do not have to be very deep; if the pencil is sharpened I poke it down to where the yellow begins. Plant 2-3 seeds per hole. Just know that once the seeds have germinated and formed their first true leaves, you will pinch off any extra seedlings. Some people find it easiest to pour the seeds onto a small plate first. I usually pour them into my palm and lick my finger and “pick up seeds” on my fingertip. Cover the hole with a tiny pinch of wet soil.
Step 4: Cover Seeds and Place in a Warm Location
Use a clear plastic cover or saran wrap to cover the seeds to retain heat and moisture. Seeds need warmth to germinate and this will trap the heat and also retain moisture. Usually a south or southwest facing window will provide enough light and warmth if you use a tray cover. Some people put the seed trays on the top of their refrigerators to get them to germinate. They don’t need light to germinate, just warmth. Don’t place them on a radiator, that heat is too intense for little seeds.
Step 5: Watering
It is very important to check the seeds daily and to water only when they appear “dry” (the soil will be lighter) or if it is dry to touch. Water pots around the edges, and if you have cut your soil into blocks or used a soil blocker, only water in the “trough” between the blocks. Never water directly on top of the seed. This could wash away tiny seeds and can cause mold to grow on the soil and cause the seedling to rot, a condition called “damping off.” Soil should remain moist, but not saturated.
Be diligent with your checking, but don’t over water. There should never be standing water in the tray. If this happens, poke a hole in the tray and let it drain fully, then reduce your watering.
Step 6: Seedling care
Once your seeds have germinated (poked their little green heads up), remove the plastic cover and place in a sunny south or southwest-facing window. Now that your seeds are up, they have used all of their internal energy and need the sun to make energy now. Just like human babies, they need lots of attention and care. Check your seedlings often and if you’re weird, talk to them. Better yet, sing to them. Seedlings can get soft, pale and “leggy” (long and spindly) if they are not getting enough light. If this is the case, you may have to move the seeds around in your space to give them more light. (I have successfully grown seeds in a south window without grow lights for many seasons.) It is also important to turn the trays or pots as the seedlings “reach” toward the light so they grow more evenly.
Step 7: “Hardening Off”
The last and maybe most important thing you need to know about starting seeds indoors is that these tender plants will need to be “hardened off” before transplanting to your garden. Hardening off simply means you give your young plants daily doses of the great outdoors for about a week before planting. Find a place out of the wind and direct sunlight to put your seedlings and leave them outside for about two hours the first day. You will continue to bring your seedlings into the house at night. Gradually increase the direct sunlight they get by a few hours each day, so they can slowly get used to being outdoors. (Yes, plants can get sunburned just like us! Watch out for white spots on the leaves. If you see them, move your seedlings to a more shaded area or dappled light). In addition, if heavy rain is expected, keep the seedlings inside as they will be damaged by pounding rain. You will need to be careful to keep them moist as they will dry out more quickly in direct light. There is nothing worse than tending to your sweet little seedlings only to see them shrivel up and get scorched right at the end due to improper hardening off. Brassicas can be planted out as early as April if they are ready and have been hardened off, as they can withstand a light frost and cooler temps. Tender plants like tomatoes, peppers and eggplants should not be transplanted into the garden before the last possible frost date. This step can be the most tedious of all, some gardeners call it the “spring shuffle”. But don’t fret; it won’t be long before you’re putting these babes into the soil once and for all.