Indoor Seed Starting 101

Starting your own plants from seed is the most economical method of growing food.  If you buy a pack of yellow onions for say, $2-something per pound,you get maybe 8 or so onions.  But you can buy a pack of seeds that has 300+ seeds for $2.75 or so and grow tons more.  It makes sense to save money on your grocery bill by planting a garden starting with seeds in most cases.

Some seeds do require a head start indoors though.  Most of the materials you will use, can be re-used year after year, which helps keep gardening affordable.  The seeds that require starting ahead indoors (sometimes as many as 15 weeks ahead of your last frost) will require a container to plant them in, seed starting mix or potting soil (or peat cubes or pellets), a way to water tender seedlings (a spray bottle works just fine for small amounts of seedlings), and a way to provide sufficient light to growing seedlings.  In our little area of Michigan, that late winter sun isn’t close enough to the earth to fuel our seedlings, which can leave them reaching for the sun and growing leggy and weak.  Supplemental lighting, such as fluorescent light fixtures, are extremely helpful for success.  A warm spot for the seed to sprout is also vital.  Different seeds sprout and grow best at certain soil temperatures, so it is important to know what those are for optimal germination.  If water, light, and temperature are not provided in sufficient amounts, you will experience spotty germination or weak and slow growth.

Extra things that are helpful include a way to circulate air around your growing seedlings (such as a small fan) and a way to hold in humidity in the early days right after planting until your seeds have sprouted (if you purchase a 72-count seed starting tray, those sometimes come with clear plastic domes to place over the top which are sufficient for holding in humidity.  If you don’t have those, plastic wrap will do just fine).

First things first…

The process of starting seeds is fairly easy.  You will first want to find out when the last frost date is for your area.  Then, decide what needs to be started indoors and when.  Some seeds, like celery, onions or artichokes benefit from a very early start – 10 to 15 weeks ahead of your last frost. Most seeds are best started in the 4-8 week range, ahead of your last expected frost.  Mark these dates on a calendar so you can see at a glance, what to start when.

The seed starting process:

To start your seeds, fill your planting container with potting mix or seed starting mix.  Do not use soil from outdoors or garden soil from your garden center.  You want the bag to read “potting mix” or “seed starting mix.”  The reasons for this are simple – soil from outdoors may contain pests or disease that will kill your seedlings, and it is often too heavy for tender seedlings to emerge from.  It is famous for developing a ‘crust’ on top if moisture isn’t kept perfect, which can prevent some seeds from sprouting at all.  It may hold too much moisture, causing your seeds to rot.  Potting mix and seed starting mix are key because they are light, retain moisture, and in some cases, will even feed your seedlings if fertilizer is included.  Seedlings don’t need fertilizer right from the start as they have food stored up in the seed, however, if they will be kept indoors longer than a few weeks, fertilizer is beneficial and in many potting soils, is already included in the bag.

Once your container has been filled, lightly firm the soil, creating a place for the seeds to be placed.  If you are like me and starting many seeds at once in a plug tray, I find it helpful to take another seed starting container of the same size (such as a 6-cell insert or a whole plug tray) and gently set that on top of the filled tray to help the seed starting medium settle into its container and create a place to place my seeds. You may also plant seeds in rows or broadcast them over the surface of a wider container, or a seed tray without the 6-pack inserts.  If planting seeds in rows in a wide, flat container, make furrows for the seeds about an inch or two apart to make the best use of your space.  If planting more than one variety of seed in the same container, be sure to mark which rows belong to which variety.

Place your seeds into the container, then cover with more soil if necessary.  Your seed packet will tell you how much, but if you don’t have specific information for your seed the general rule is to plant the seed 1-2 times its diameter. Teeny tiny seeds may not need to be covered at all, but rather gently pressed into the planting medium.  I water all of my seeds once the seed has been set in the planting medium, and the watering helps press the seed into the soil instead of doing it by hand.


Once your seeds have been planted, this is a great time to water them. Be sure that whatever container you use has holes for proper drainage.  I like to give my seeds a thorough watering at this point and then sometimes I cover them with plastic wrap (not wrap tightly, just cover to retain humidity).  From this point on, any watering will be done with a spray bottle.  Generally, I don’t need to water the trays again that have plastic wrap on them until the seeds sprout, but this can vary considering some seeds can take up to three weeks to germinate.  I avoid heavy watering from there on out though, to prevent the seeds from rotting.


Some seeds require light to germinate, such as celery.  For these seeds, they get put right under lights for 12-16 hours per day as soon as they are planted.  Other seeds don’t require light until they sprout, so they are set in the greenhouse on an unlit shelf until I notice the first germination occurring, then they are placed under lights.  All seedlings do require light, and in many cases late winter sunlight coming through the window is not sufficient.  The closer to spring you get, the better the sun will be, but for the early season stuff you will need supplemental lighting. I have found great success using fluorescent light fixtures, also called shop lights, and I have two of these per shelf on many shelves in my greenhouse.  You can choose to use grow lights, but they are unnecessary for sprouting seeds.  If you want to grow plants to the point of flowering or fruiting, you will need grow lights.


Check the optimal soil temperature for seed germination and growing (these may be different) and plan accordingly.  Place your seed tray in a suitable location – such as on top of your refrigerator, near a wood stove or other heat source, or on top of a heat mat made for seed trays (keep the mat on 24 hours a day, and turn it off once your seeds sprout). Then, it’s time to wait.

While You’re Waiting…

Check your seed trays twice per day to turn on/off lights, check moisture and consider temperature to be sure it’s not too hot or cold.  Make note of what seeds you started and when, then figure when you can expect to see sprouts poking through the soil. Once you notice seedlings poking through the dirt, it is usually safe to remove the plastic cover you may have been keeping on them for humidity and remove the heat mat, if you were using one.  At this point, keeping the soil moist enough but not too wet is critical, especially once any protective coverings have been removed.  If you have not yet placed your seeds under lights, once they sprout it is critical that they are able to be put under artificial or natural light. If using artificial light, set the light within a couple of inches of the tops of the seedlings, and raise the light as they grow. Seedlings should get about 16 hours of light per day.

From here, maintain daily care.  You may need to fertilize the seedlings after a few weeks, and depending on how fast they grow you may need to “pot up” or transplant the seedlings to a larger container before they are ready to head to the garden outside.  We will talk about these things in later blog posts.


Here are some pictures of seeds in the process of sprouting.  I set up a 4×8 greenhouse in the basement and placed four of the 4-shelved mini greenhouses in there (4ft wide) for shelving.  Some of the shelves have 2-4ft shop light fixtures per shelf and I can fit 4 seed trays per shelf. In here I keep a oscillating fan and a radiant heater, to provide air circulation and temperature control.

Storing Seeds

While the planting season may be over, there is still some work to be done before we can sit back and relax for the winter. One of these things might be doing something with left over seeds.

If you’re anything like me, you probably have some left over seeds from this past season. Maybe you’re wondering if they will “last” and germinate after so long. The good news is, Yes! Your seeds will carry over into the next season – and beyond – with proper storage. This is great news because now you can buy seeds off the clearance rack with confidence as stores look to get rid of their stock and save some money on next years planting.

There are a few things you should know when it comes to seed storage. In order for seeds to remain viable (produce strong seedlings) and have a good germination (sprouting) rate, you need to keep them dry (low humidity), cool, and in a dark place.

My favorite way to store seeds is in a glass jar with a lid that has a rubber seal. I store seeds right in the jar if I have enough, or I store the seeds in the original packet, right in the jar. It’s perfectly fine to store different varieties together in the some container. I have also put seed packets together by type and stored them in a ziplock bag. Don’t forget to label the container. Then, store in a dark place. Light will actually break down the seed coating, which opens the ability for bacteria and fungus to break in and destroy your seed.

Seeds prefer to stay cold, so you might even store your seeds right in your refrigerator or freezer. Suggested storage temps are under 50F. A handy tip I learned is that ideal storage is the total degrees F + the % of humidity should be under 100. If you aren’t sure about your humidity, you can buy a hygrometer that will measure the humidity in the air. I bought mine right on amazon and it serves a couple of purposes around here – i also keep track of the humidity in my egg incubators with it. Very handy.

Keep your seeds dry – both before you intend to store them, and during the storage process. You can buy desiccant packs to place in each storage jar to help remove moisture and ensure your seeds stay dry. Additionally you can buy silica gel at most craft stores and make your own – or even vaccuum seal your containers. Make sure your seed packets don’t get wet – once your seeds get wet, it’s very difficult to store them with success.

Germination Test: If you are questioning whether your seeds will sprout before taking the time to plant them in your soil, you can perform a germination test. Take a few seeds and place them on a moist paper towel. Fold it up and place inside a ziplock bag, then place the bag in a temperature controlled area that matches the best temp for germination for that plant. After the number of days suggested for germination, take a look and see how many sprouted. This will give you a good idea on whether they will sprout or not – but this won’t be a good indication on viability – often, viability will decrease before germination rates will, so even though the seed will sprout, it may not grow strong.

Here is a handy chart!

Think Ahead: Make Simple Beds Now!

As a gardener, I am constantly thinking ahead. My thoughts never stop at the current years garden, I try to think years ahead. And every summer/fall I feel like I am thinking more about the next years garden than I am about my current garden. This is because successful gardening benefits from planning and preparation. I am going to share with you an idea to easily make permanent garden beds without having to dig or rototill. This will create a bed that you won’t need to rototill, but thanks to earthworms and other creepy-crawlies underground, your soil won’t need it.

A few years ago I started making a big change toward no-dig beds in my garden. I usually have about 60 beds, but I change the nonpermanent bed structure around from year to year, but I generally have around 60 beds and a few bigger plots for corn and squash. Because of how many beds I have, and the fact that my garden is tended to be me and my children, going 100% no till is a process. I don’t have a tractor, or superhuman strength, but each year more and more beds get converted and it will be a work in progress for another couple of years. If I can do this while homeschooling eight children, it gives me hope that anyone can get a bed or two put together without having to rent any equipment or spend hours you may not have. I don’t even use a tiller to make my beds in the fall anymore!

All you need is cardboard, compost, and mulch. And if you start your bed now, it should be ready to plant into in the spring without much prep work at all. I have spent many a spring tilling, pulling weeds, and spending so much time preparing beds when I should be sowing seed and transplanting. Switching to no till beds has been a big time saver in the spring, then I can put time into them to refresh them later in the season.

If you are frugal-minded (I am, so I thought I’d share some ideas to keep costs low), you can save cardboard from your household, ask friends to save , or ask local stores if you can take some of the cardboard they are discarding. I have a store locally that will let me take all the cardboard I want! Stay away from boxes that have been covered in wax or a glossy finish. As far as compost, many farms are willing to just give it away if you have a way to haul it. Some will let you drop a trailer at their farm and they will fill it when they clean their barn, others may have a tractor that they can load their manure pile into. If you are really lucky, they may have manure that has already aged and is just sitting around! If you have rabbits, their manure is like garden gold – it doesn’t require aging and it does lovely things to your garden. As far as mulch, if you have an accessible spot you might be able to talk your local tree service into dropping a load of tree mulch in your driveway or backyard, maybe a friend will have a spoiled bale of straw, maybe you can save newspaper and ask that your friends do, too. Here are some mulch ideas.

I am going to assume you know exactly where you want to place your bed. I will write up a post about garden planning soon. You want to be sure your spot has enough sunlight, fertile soil and good drainage before placing a bed on it. Then cut the grass nice a low, lay cardboard down completely covering your bed, then pile on compost. Depending on the time of year you are doing this, mulch (if you choose to use it) can be put on right away or wait – I prefer to make new beds in the fall, or at least get the cardboard and compost on. Then, after a good frost I will put the mulch on (though, admittedly, I have put mulch on any time of year just because if I have the time, I need to take it… but my preference for topping with mulch is after a good frost). That is the basic idea.

Some people prefer to rototill the soil before placing cardboard on. Some people prefer to dig out the center and place old/moldy straw or hay in the center before piling dirt back on. There are a variety of ways to go about this.

You can do rows or your entire garden. I do rows, about 50ft long, about 4ft wide and I leave a small path to walk on and get a wheelbarrow down. to keep the paths walkable, I use a weedwacker and go over the grass once a week in my aisles.

As far as upkeep, each year I place a new layer (though not as thick) of compost on at least once a year, if not a couple of times depending on if the crop I am growing is a heavy feeder or not. I also refresh the mulch once a year with a few inches of wood chips that have aged a year, or moldy hay.

Time Saving Tip: Use Mulch

Mulched Beds

One of the biggest complaints I hear about gardening is that it takes up too much time. All the weeding and watering sure does take up a lot of time. I used to spend hours in my small gardens, pulling weeds, watering religiously, checking plant progress and trying to troubleshoot. I became discouraged because this gardening thing really was taking up too much time. I had kids to care for, a home to take care of, I didn’t even have a job outside the home to add to the mix but I knew if I did, gardening could never happen. I hear this so often, and want to encourage you that there are things you can do to help reduce time spent performing basic tasks.

One thing I have found to be a huge time saver is using some sort of a ground cover – a mulch – to cover the dirt and smother weeds. Over the years I have used various mulches – wood chips, compost, newspaper, cardboard, grass clippings, weeds pulled from others beds, animal bedding (aged at least 8 months), old feed bags, fresh straw, moldy hay, leaves. I have had various levels of success, which I will get into in a minute.

Using a mulch performs several different functions:

  1. Smothers weed seeds, preventing their germination. You may still have some weeds, but they will be far fewer and pull out so much easier.
  2. Keeps the soil moist, as moisture won’t evaporate as quickly.
  3. Aids in reduction of erosion – both from wind and water. Lighter soils can suffer topsoil loss with heavy winds, and gardens placed on a slope can experience erosion due to water drainage. Mulch helps prevent these problems.
  4. If the mulch is of an organic nature, it will break down and help benefit the soil.
  5. Reduces the splashing of dirt and rainwater on plants, which can prevent the spread of disease and keep your vegetables cleaner.
  6. Organic mulches will decompose, adding nutrients and humus to your soil.

There are a few things you should know –

  • Mulch doesn’t work well being placed on top of weeds that are already growing vigorously. You will need to remove those weeds before applying the mulch. I typically pull the bigger weeds by hand, then use a weeding tool to run over the surface of the soil and remove any smaller weeds I may have missed. You could also till the garden bed before laying mulch. If you plan on making a ‘no till’ or ‘no dig’ bed ( a garden bed that is not tilled each year – I will get into this in a later post), use some sort of a barrier as the bottom layer – my favorite for beds that I am going to plant different crops in year after year is simply plain cardboard. For beds that I will not be digging in yearly, such as strawberry beds, I just old feed bags as the bottom barrier. You might prefer some other weed barrier that will not break down such as black plastic.
  • You would apply an inorganic mulch, such as plastic, before transplanting. You then make holes at proper spacing for the vegetable you are planting when you are ready to transplant. Organic mulches should be applied after the plants are well established, unless you are planting into an established no-till bed, then it will already be there.
  • Wet the mulch once you apply it, to help give it some weight that will help smother weeds, and compact the mulch enough that sunlight cannot get through. Or better yet, plan to mulch ahead of a nice, soaking rain. I try to plan as many gardening related tasks as I can before and after a good rain! do make sure there is some moisture in your soil either way, because it will take quite a bit of water to penetrate new organic mulches and water intake will be limited on plastic mulches.
  • Plastic mulches will heat the soil, and organic mulches will act as an insulator. Applying plastic in the spring will help warm the soil and benefit plant growth.
  • You can find most, if not all, of your mulch needs for free if you are creative enough!

Common Mulches:

  • Hay or Straw: Use 6-8 inches, plan on refreshing through the season as they will break down rather quickly. Ideally use moldy, spoiled hay/straw, as you should have less weed germination. You will more than lightly battle with weeds if you use fresh hay or straw. The weeds that do germinate are generally very shallow rooted if you get to them quickly, and pull up easily, but they can be a pain.
  • Grass Clippings: Start with about 2 inches of untreated grass clippings and build up as needed with dry clippings.
  • Leaves: Layer 2-3 inches thick and add new as necessary. Leaves do break down quickly, but they improve the soil also. Do avoid excessive use of walnut or other nut leaves due to the presence of juglone, which can inhibit the growth of your plants. The tree its self and the roots contain the most of it but there are small amounts in the leaves. A small amount should not matter, but if that is your only source of leaves, you may want to consider a different mulch.
  • Compost: 2-3 inches of a well aged compost is beneficial for plant growth, though it may be better off incorporated into the soil or used in conjunction with a barrier of some sort – weeds will pretty easily grow because it is an excellent soil amendment.
  • Wood chips, bark: 2-3 inches is best and provides excellent weed control. It takes longer to decompose, so the need to refresh through the season will be minimal.
  • Newspaper: 2-4 layers will provide good weed control, either shredded or whole. There is a higher likelihood of sunlight getting through shredded paper though, and it likes to fly away when dry so be sure to wet it right away. Avoid glossy inserts.
  • Black plastic: One layer is all that is needed. While it wont’ break down as quickly as organic mulches, it will begin to deteriorate and need to be replaced at least every two years. This will cause the soil to heat up – about 8 degrees (F) in the spring and higher as the summer progresses. To avoid the soil getting too hot and stressing or killing your plants in the summer, you should apply an organic mulch on top of the plastic to avoid direct absorption of sunlight.
  • Clear plastic: Don’t use clear plastic. It creates a greenhouse effect with weeds and provides a great place for them to grow! Heat + Sunlight + Retained moisture = happy plants – and weeds. It is helpful for warming soil in the spring, but remove it before planting.

My Personal Faves:

I have had great success using newspaper with grass clippings on top. The newspaper was quick to break down but provided a great ground cover. The grass clippings added weight to the newspaper which kept it from blowing away or tearing easily. Since we bought our farm, using grass clippings is no longer an option as our only mulch because we don’t create nearly enough of them on our own (I still use them, just not as my only source). I have used straw and hay, and I am not a fan of straw. I do like using moldy roundbales of hay though – I roll those out on a bed I’ve lined with cardboard to create a ‘no till’ bed. The hay is already compressed, so I just have to make a hole and plant through it. Beds that I plan on tilling the next season don’t need cardboard. I like to keep the soil covered whenever possible, and sometimes that happens with weeds I have pulled from another bed when things have gotten out of hand. I pick up trailer loads of cardboard from a local store that discards them, so this is a free bulk source. My favorite way to mulch is using wood chips on top of compost. I don’t till the wood chips in to the dirt, but leave them on top. I don’t till these beds at all. I add new compost yearly and wood chips as needed. We offer to be a drop spot for local tree services who have, thankfully, taken us up on the offer. I age the wood chips a year before adding to the beds.

What if you CAN’T get a hold of mulch for some reason? Maybe you’re too late in the season, or you don’t have a way to bring mulch to your garden, or whatever the reason may be, maybe you need to leave your garden beds bare. Many people do, it isn’t the end of the world. Weeding will be a little more tedious, but in those cases, frequent weeding is essential with the right tool! I can’t stop singing praises about the Hula Hoe, ever since I found it, that $16 dollar tool has changed my gardening life tremendously!!!! Anyway, if you get in the garden every few days or so and lightly run a weeding tool over the surface, you will nip weeds before they have a chance to take deep root. I love the hula hoe because it will skim the top layer of dirt and slice weeds at the soil surface without disrupting the established root system of your vegetables. A frequent and quick skim of your garden beds every few days will keep the weeds at bay.

Do you use a mulch? Do you have a favorite?