Seed Starting for the Home Gardener.

Every year, I see on some group discussion post, a VERY heated debate about the best way to start seeds indoors. Here is the real truth. The method that works for you, is the best for you. It might be different from your neighbors and that is okay. 

There are different stages of raising seedlings.

The first step of this is germination. For this, soil temperature and light requirement are what matter most, keeping the soil at a decent moisture level is also fairly important. This is where a seedling heat mat can be very important to get the soil warm enough. Now some seeds can germinate at relatively low temps, while others need much higher temps. For example, Delphinium germinates at 65-70 degrees F while zinnias germinate at 80-85 degrees F. And this is soil temp, not air temp. So if you are trying to germinate zinnias in your 65 degree air temp basement, it won’t go well because soil temp is generally about 15 degrees lower than air temp. Your standard seedling heat mat will raise the temp up about 15-20 degrees from whatever the room is at, but you can get fancier options that allow you to control the amount of heat being put out if you need more or less than that 15 degree difference. 

The next important key to germination is light. Some seeds like snapdragons require light for germination while marigolds can have the seed be covered. At this stage however, fancy growth lights aren’t required, just some window light would be fine. Use caution when running grow lights and seedling heat mats at the same time as this can cause your soil to dry out very quickly. 

While buying cheap seeds might seem like a good place to start as a home gardener, some of the cheap seed packages offer the most generic advice for all their seeds, and sometimes it tells you the wrong thing. I advise you to invest in seeds from companies that put detailed information on the packaging, or on their website, but really I want you to have it on the packaging so you don’t have to go looking. Johnny’s Selected Seeds is fantastic for this. (Not a sponsored post, I just believe in their company values.) Lisa Mason-Ziegler of the Gardeners Workshop also gives a lot of great advice for home gardeners and she has written several books as well and has lots of videos if you are a visual learner. (Again, not sponsored, just want to guide you in the right direction.) You want seed packages that tell you germination temps and light requirements, as well as germination rates. Some varieties naturally have lower germination rates so you may want to sow a few extra seeds if you are counting on a certain number of plants. 

After germination, this is where you need to get high quality lighting in place. If your lights are too far away from your plant or not as bright as they need to be, this is when you start to see seedlings stretch or get “leggy”. This is bad for your seedlings. The general recommendation is keeping your lights a few inches away from your seedlings. For me, this means having shop lights on chains that I raise and lower as needed above my shelves of plants, but I have also used smaller grow light setups that had one light that could be raised and lowered. If your lights are fixed you might be able to stack something under your seedlings to bring them closer to the light. Inexpensive shop lights can work in place of the more expensive grow light bulbs. Traditional lights also throw more heat than LED lights so keep that in mind for your watering schedule.

At this point, you can turn your heat mats off unless you are trying to grow tomatoes in a cold basement where the plants want warmed soil. 

Fertilizer is the next piece of the puzzle. If you use a seed starting mix, there is little to no nutrients in there because seeds come pre-packed with what they need for germination which is what these mixes focus on as they usually have very small particle sizes. This is meant to achieve good soil contact for keeping the seeds moist and making sure they don’t get buried if they are seeds that need light to germinate.  After that, to keep your seedling growing, you will need to feed it. READ THE INSTRUCTIONS on your fertilizer. A good one will have instructions and possibly different ratios for seedlings. Too strong or too much fertilizer can kill your seedlings faster than using none at all. I won’t get into the organic vs. inorganic debate today. I prefer something natural like Neptune’s Harvest. (Again, not sponsored.) If you are using a mix that has fertilizer in it already, use extreme caution with adding more. 

Growing out, it is important to keep the soil at a good moisture level. You don’t want your plants sitting in water all the time, so if you are bottoming watering, that tray needs to dry out before you water again, same with if you are soil blocking. You want the soil to be relatively dry, but not so dried out you have wilting. Keeping the soil too wet can cause a problem called dampening off, where the plants rot off right above the soil line. You may also get fungal growth or moss/ algae growth depending on your mix. If you start to see those signs, back off on your watering schedule. 

You want to make sure that you can size up the soil of your seedlings to keep them from getting root bound or you want to time it so they are ready to go out in the garden before they out-grow their home. 

I hope this helps you feel more confident about seed starting this year. If you have any questions, please feel free to drop them in the comments or send me an email  at ebecka@beckasblooms.com.