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How To Start Seeds FAQ


 Seed Starting FAQ:

This FAQ is based on how I start seeds. Many variations to my methods of doing things are equally valid. But I can only tell you how I do it – I don’t know, in any significant degree of detail, how other people do it. My way of starting seeds works for me so I am certain that if you follow my directions carefully, it will work for you too. If you find another way that works better for you or is more convenient for you, that’s obviously fine. I do mention alternatives in a few cases.

OK, here goes – in question and answer format. You can click on a question (immediately below) to go directly to its answer or you can browse through all the questions and answers by clicking here.

1. How do I know when to start a particular seed?

2. What containers should I use for seed-starting?

3. I see that some people recommend starting seeds together in a larger container, and transplanting them to 6-cell packs when they have two sets of seedling leaves. Why don’t you recommend this?

4. What seed-starting medium do you recommend?

5. Can I put more than one type of seed together in a 6-cell pack?

6. OK, I have the seed-starting mix, and the 6-cell packs, and seeds, and labels: and I’m ready to start seeds. Now what? What do I actually do?

7. Now my seeds are sown. What next? Where do I put the 6-cell packs?

8. One of my seeds has sprouted! Now what?

Questions and Answers

1. How do I know when to start a particular seed?

First, you need to know your expected last frost date. If you do not know it – and you’re in the USA – contact your state’s Cooperative Extension: either using their website, or phoning your local (county) Extension Agent. Links enabling you to find both are on our Resources Page. (If you’re not in the USA, I’m sure the equivalent information is available somewhere in your country, but I can’t help with that.) Asking a neighbor who has a vegetable garden can help too – assuming that your neighbor’s information is accurate. Gardening neighbors of mine have given me some wildly inaccurate answers to this question.

Then, knowing the last frost date, you consult the growing directions for the particular plant. These will usually say something like this: “Start seeds 10-12 weeks before last frost date” or “Start seeds 1 to 2 weeks before last frost date.” There are also some tables giving these dates, and they are handy. One is located here. Many gardening books also have such tables.

If you see directions such as “Start seeds May 1,” you need to be wary. What area was the writer referring to? By May 1, the weather may already be too warm for lettuce to grow happily in Southern Florida or California, for example, whereas other areas may have a foot of snow on still-frozen ground.

2. What containers should I use for seed-starting?

After experimenting with many types of containers, I settled on 6-cell packs. They are space-economical, they aren’t tippy, and my seedlings grow very well in them. They are reusable and – with reasonable care – will last quite a few years. Their only disadvantage is that it’s almost impossible to buy them in small quantities (although we are selling them as a convenience for our customers). Of course, if you buy seedling plants at a nursery, then you can save the packs.

Other possibilities include:

Foam coffee cups – they aren’t space-economical and they are tippy. They also use quite a bit of your seed-starting mix, but otherwise they are OK. Punch drainage holes in the bottom with a pencil.
Little paper cups (about 3″ high) – I think these are sold for use in bathroom paper-cup holders. These work fairly well. Punch drainage holes in the bottom with a pencil.
Eggcartons – I don’t like them because there’s so little room for seed-starting mix (or the plant’s roots) that you will quickly have to transplant all your little plants. This adds an additional and unnecessary step to the process. Punch a drainage hole in the bottom of each little cup if you use these.
Yogurt cups – not space-economical and not seed-starting mix-economical. Otherwise probably OK, assuming you have a lot of them. Punch drainage holes in the bottom.
Peat pellets – I have never used them, but a friend of mine likes them. They aren’t reusable, and therefore probably somewhat expensive. I’m somewhat skeptical of them because of my bad experiences with peat pots (see below). On the other hand, they include seed-starting mix: they are the container plus the mix.
Peat pots – I’d like to warn you about peat pots. I’ve tried them several times and had very poor results with them. For one thing, you have to water the little plants much more often than with other containers, as they dry out very fast. For another thing, I have had several plants mysteriously just refuse to grow after being transplanted outdoors in their peat pots. The idea is that you leave the little plants in their peat pots, and just bury the peat pots in the soil and they will dissolve away into the soil. (In fact, you must do it this way: the plant’s roots will grow into the walls of the peat pot.) Well, in several cases of plants refusing to grow for no apparent reason, I finally dug up the roots and discovered that the peat pots had not dissolved at all, and the plant’s roots were still confined mainly to the peat pot, months after being transplanted outdoors. So I do not recommend them.

3. I see that some people recommend starting many seeds together in a larger container and transplanting them to 6-cell packs when they have two sets of seedling leaves. Why don’t you recommend this?

I just cannot see the point of it. It adds an extra and unnecessary step, more work. It is certainly not necessary and I don’t do it. I want to keep the process a simple and easy as I can.

4. What seed-starting medium do you recommend?

    My first recommendation: A commercial seed-starting mix, available at local garden centers and nurseries.
Advantages: This is designed for starting seeds, it’s a fine mix. It’s sterile (to prevent damping-off: a fungus that results in the sudden death of seedlings). It’s just right for the job.
Disadvantages: None, if starting seeds on a fairly small scale (as most container gardeners probably do). It’s a little expensive if you need to buy several packages per season.

My second recommendation: A commercial, all-purpose soilless mix, available at local garden centers and nurseries. One popular brand is “Pro-Mix” and another brand is “Jiffy-Mix”. There are several others and I have used various brands with uniformly good success. This is what I use because I start so many seeds that the seed-starting mix gets a bit expensive.
Advantages: Economical when bought in larger quantities. Sterile. Works very well. Is very versatile: you can also use this when you transplant the little seedlings into larger containers indoors (tomatoes, etc.) or as your indoor or outdoor potting soil.
Disadvantages: Can be a bit coarse for the smaller seeds. You can strain it through a piece of 1/2″ or 1/4″ mesh hardware cloth to get out the larger pieces. I very seldom bother to do this, though.

My third recommendation: A mixture of one part peat or sphagnum moss or coir (coconut fiber), one part (purchased and sterile) potting soil, and one part horticultural vermiculite (or perlite, or sand). I used this before soilless mix was readily available. I wouldn’t dream of using it now.
Advantages: Maybe someone, somewhere, can’t purchase soilless mix locally.
Disadvantages: The inconvenience of having to buy three things, store them, mix them, etc. It’s a nuisance, and I believe that it is not as good for the task as the others listed above. But it will work. I did it for years: I used four big garbage pails for storage: one for peat moss, one for potting soil, one for vermiculite or sand, and the fourth for the already-mixed medium.

WHAT NOT TO DO: Do not use unsterilized soil from your garden. It will probably have organisms that cause damping-off, and this will result in the death of your seedlings. In almost all cases, garden soil is also too heavy for good drainage in a container. If you have no other choice and must use garden soil, you must sterilize it first. I recommend Nancy Bubel’s book “The New Seed-Starter’s Handbook” for information on using garden soil.

    5. Can I put more than one type of seed together in a 6-cell pack?

    You really shouldn’t. For starters, they would probably germinate at different times and this would be a problem (as you’ll see below). Also, watering requirements would be different, etc.

6. OK, I have the seed-starting mix, and the 6-cell packs, and seeds, and labels: and I’m ready to start seeds. Now what? What do I actually do?

    First, fill as many 6-cell packs as you plan to use with your seed-starting mix. The next step is to get the mix wet. Seed-starting mixes (and soilless mixes) all resist getting wet but I have found that using the hottest tap water available will get them thoroughly wet. So I take the 6-cell packs to my kitchen sink and get them thoroughly wet using very hot water. Then I either let them sit overnight (to cool down) or run cool water through them to cool them down. (I don’t want to put the seeds into scalding hot seed-starting mix.)

I know some people put a large quantity of seed-starting mix in a bucket, and get it all wet first, then fill their 6-cell packs (or whatever containers they use). I’ve tried this, and I just don’t find it as easy and quick as filling the containers first, then getting the mix wet. But either is fine: whichever you prefer.

howToStartSeedsNext, assemble the items you need to start the seeds. The picture to the left shows you what I use:

6-cell pack filled with now-damp seed-starting mix
Saucer, in case the 6-cell pack drips
Packet of seeds
Scotch tape
One little dish with water
One little dish with nothing in it

Here’s what I actually do:

First, I write the seed’s name, variety, and the date on a label, using the pencil.
Second, I shake a few of the seeds into the dry little dish.
Third, I dip the toothpick into the water in the other little dish.
Fourth, I use the toothpick to pick up one seed at a time and place a seed (more often two) in each cell of the 6-cell pack. (I dip the toothpick into the water again for each seed.)
Fifth, I smooth just a little of the seed starting mix over each seed, using a finger.
Sixth, I put the label in the 6-cell pack.
Seventh, I shake unused seeds from the (dry) little dish back into their packet.
Eighth, I scotch-tape the seed packet closed and put it away until the next time I will use it. It is best to keep your seeds under refrigeration, if you can.

Finished! In the case of very large seeds, I will skip the toothpick and just drop them into place with my hands. Very large seeds also get pushed down a bit into the mix (I use the eraser end of the pencil to do this). In the case of really tiny (almost microscopic) seeds, I have to be content to put several together in a clump, as this cannot be helped. There are some exceptions to this procedure: some seeds don’t get covered at all as they need light to germinate. But basically, that’s how it’s done.

I usually put two seeds in each cell. When they have both sprouted, I will cut one off with a small pair of scissors so the other will have room to develop. (Do not pull one out, that may disturb the other’s roots: use scissors.) Sowing two is just insurance – it insures that I get at least one that sprouts. In the case of expensive seeds, I don’t do this – then I just put one seed per cell.

        7. Now my seeds are sown. What next? Where do I put the 6-cell packs?

        Many, probably most, seeds will germinate well and quickly in temperatures from around 70 – 85 F (21 – 29C). This is just a bit warmer than average house temperatures (well, it’s warmer than we keep our house anyway). In other words: they pretty much want the same conditions that bread wants while rising. There are several possibilities for keeping your seeds warm while they are germinating:
Use of a seedling heating pad (commercially available at many online sellers). These tend to be expensive.
Use of a mini-electric greenhouse (commercially available at several online sellers). I have two of these. Their floor space is 17″ x 11″ (each) and each will hold eight 6-cell packs (stacked in two layers). One cost me $30 and the other (on sale) $15.
Putting the seeds on top of a refrigerator or freezer – if the top is warm.
Putting the seeds on top of a hot water heater.
Putting the seeds on top of a heating pad (the kind used for arthritis and so on) with the heating pad set on “low” and wrapped in a thick towel.
Heating a brick or stone in the oven, wrapping it in a towel, and setting the seeds on it. Reheat from time to time….
Putting the seeds on a sunny windowsill.
Putting the seeds in an oven, with the oven OFF, but the oven light on. (If you forget and turn on the oven: total disaster! Maybe even a fire.)
If you cannot provide a warm place like this for your seeds while they are germinating, they will probably sprout anyway, but it will take them longer.

Unless your seed will be in a closed environment (mini-electric greenhouse, etc.), it’s a good idea to cover the cell-pack loosely with a piece of plastic wrap (cling film) or a plastic bag to keep it from drying out quickly. You need to keep the seed-starting mix damp (but not dripping wet) while the seeds are germinating. I use a spray-bottle (mister) for this.

These are what I think of as “standard conditions” for seed-sprouting. There are exceptions to the standard conditions: some seeds need cooler temperatures to germinate. Some need total darkness to germinate. Some seeds need light to germinate. Some seeds need to be chilled before they will germinate (but these are mostly shrubs, trees, or perennials). Refer to your seeds’ growing directions for this information, or to a book such as The New Seed-Starter’s Handbook or Park’s Success with Seeds. Many other gardening books also have this information.

8. One of my seeds has sprouted! Now what?

        Remove the covering. Put the covering aside, and do not cover your seeds again. Take the seeds off the heating pad (etc.), and don’t use the heating pad again. They no longer need such warm temperatures and, in fact, somewhat cooler temperatures are better. Ordinary room temperatures are fine from here onwards. Put the 6-cell pack into as much light as you can give it: under fluorescent lights or on a sunny windowsill. I do this as soon as even one seed has sprouted. The others will sprout very soon. (This is one reason why you didn’t mix the types in a 6-cell pack.) The cell pack will, of course, need to be set in a flat (plastic tray made for this purpose), or a dish, or a foil pan so water doesn’t drip on to the surface below.

Now your seedlings are little growing plants. Keep them well-watered: bottom watering (setting the 6-cell pack in a dish of water and letting it take up water slowly) is usually recommended and I do use it for tiny fragile seedlings (but it takes more time, so I top-water more robust or larger seedlings). They will need to be fed, as all plants do, but with dilute plant-foods. I first feed seedlings about a week after they have sprouted, and then I feed them about twice a week with an all-purpose plant food (or all-purpose house plant food) DILUTED TO HALF STRENGTH (half the strength recommended on the container). Fish emulsion can be used instead of the all-purpose plant food, but if you have a cat, it may be a problem: the cat may want to dig up the seedlings because of the fishy smell.

Give your seedlings as much light as you possibly can. If you are using fluorescent lights, the lights need to be just a few inches above the seedlings: about 2″ above the little plants is perfect. Lights can be hung on a chain and raised and lowered as the plants grow, or the plants can sit on something (egg cartons? books?) and be raised and lowered. Seedlings should have a “night time” when the lights are turned off. I turn our fluorescent lights on around 6 am and turn them off around 10 pm each night. The ideal is 16 hours with the lights, 8 hours in the dark, each day (very like the human day/night cycle). Some people use timers for their lights.

My fluorescent lights are ordinary, cheap, 4′ long shop-lights with ordinary, cheap cool-white, 40 watt, fluorescent bulbs. A combination of warm white and cool white might be better, but I can never find warm-white bulbs. You need to be careful to get 40 watt bulbs: there are some 4′ bulbs that are lesser wattage.

If your seedlings are growing in a sunny windowsill – and it really does need to be a sunny windowsill – it helps if you can reflect the light back at them, by a covering a piece of cardboard with aluminum foil (shiny side out) and supporting it inside of (towards the house) the seedlings. Foil can be used underneath the seedlings too: or they can be set in a foil-lined open box (such as a shoe-box). If your seedlings are growing tall and splindly, they are not getting enough light.

Sometimes, seedlings will outgrow their 6-cell packs before before it’s warm enough for them to go outdoors. This is often the case with tomatoes, peppers, and eggplants. They cannot be put outdoors until after the last frost in spring. Then you will need to transplant the seedlings into a larger container: I use 4″ square pots for this. If you’ve started your seeds way early, you may even need to transplant them another time before they go outdoors. This is a nuisance, but it will get you more-developed, larger plants to transplant out, and earlier tomatoes (etc.). (If you have a long frost-free season and/or you don’t want to have to transplant anything more than once, then just start the seeds a bit later.) On the other hand, plants such as lettuce that like cool weather won’t need to be transplanted indoors at all: they can go out in early spring.

Your seedlings cannot be transplanted outdoors without either being “hardened off” or protected in some manner. “Hardening off” the seedlings means taking them outdoors for increasing amounts of time over several days, starting with one or two hours per day and building up to all day. This gives them chance to gradually become accustomed to stronger sunlight, winds, etc. I find this to be a terrible nuisance, and I don’t see how people who work away from home all week could possibly do it. Therefore, I protect my newly-transplanted seedlings instead. There are various methods of doing this: the idea is just to keep most of the sun and wind away from them for a few days. I will cover hardening off or protecting the little plants and transplanting them outside in a subsequent article, to be posted soon.

I hope this all makes sense to you. If you’ve never started seeds before, reading a book such as “The New Seed-Starter’s Handbook” (or one of the excellent general-purpose gardening books reviewed in our Bookstore) would probably be extremely helpful.