Archive for the ‘Seed Starting’ Category

Seedling heat mats speed up germination

Friday, April 11th, 2014

For many years I started seeds without using a seedling heat mat.There never seemed to be any problems doing it that way as long as I was able to find a warm spot for my seed trays. Those were the days when the tops of refrigerators radiated heat and were nice and warm. That was the best place to germinate small amounts of seeds because the constant heat warmed up the seed starting containers to the ideal temperature. Small heat mats for home use were not readily available back then.

It wasn’t until I worked in a large private greenhouse that I really found out the advantages to using bottom heat. I needed to grow thousands of flower and vegetable plants from seed. Time was, and still is, a valuable commodity, I couldn’t afford to wait for seeds to sprout.

Seeds I grew on heat mats seemed to jump up through the soil surface compared to their unheated brethren — germination percentage went up too. After the first transplant growing season, I invested in a few large commercial heat mats.

These days, nearly all garden centers sell small heat mats. They are usually preset at a specific temperature and are not adjustable, unlike the commercial mats.

Heat mats last a long time if used properly and are carefully stored.

Heat mats last a long time if used properly and are carefully stored.

The small mats work just fine for small amounts of seeds. By small amounts, I mean you can still germinate enough seeds to grow hundreds of plants. That’s more than enough for an average home garden.

If you are even a little bit serious about growing plants from seed, a seedling heat mat is an essential investment, especially now that refrigerators aren’t warm anymore.

Bob

Artificial light for growing seedlings

Friday, April 4th, 2014

Plants need light for photosynthesis and without light they can’t grow. But not all light is equal.

If you remember from your middle school science class, sunlight contains many colors or wave lengths of light. Plants mainly use the blue and red part of the light spectrum and not much else.

Seedlings need good quality light to thrive. The ideal place to grow seedlings of course,  is in a greenhouse or sun-room where there is plenty of natural sunlight. However, not everyone has access to a space like a greenhouse. A south window can help, but even in that case, supplemental lighting may be needed.

An adequate substitute for natural sunlight is light from fluorescent bulbs. Special “grow lights” are available but are quite a bit more expensive than standard fluorescent tubes and they don’t last as long. Research has shown that plants do as well or even better under “cool white” bulbs. Cool white bulbs provide plenty of blue light.

Even with the most recent research, some gardeners still feel that seedlings grow better if the light is “blended”. So, they’ll add a “soft white” bulb to a florescent fixture to provide some red light for their seedlings. Shining light from an incandescent bulb onto the seedlings will also add some red light.

You don't have to spend a lot of money on light fixtures. I bought this on at a garage sale for less than a buck.

You don’t have to spend a lot of money on light fixtures. I bought this one at a garage sale for less than a buck.

Most vegetable and flower garden seedlings need bright light, at least 500 to 1,000 foot candles. Placing the light fixture within six inches or so will provide them with that amount of light. Still, that is not a bright as a sunny day where there can be 10,000 foot candles shining on a plant.

Plants require some darkness every day so lamps must be on a timer. Six to eight hours of darkness is sufficient for most plants — just about the same number of hours as a good night’s sleep.

If you are really serious about growing a large number of plants under artificial light, special high output light fixtures are available starting at around $300 each.

Bob

Starting Seeds at Home VIII

Wednesday, April 7th, 2010

Once you have transplanted your seedlings  into their final growing container, continue your fertilizer and watering schedule.  If you are growing them under lights, raise the fluorescent tubes as needed.

Check to be sure the seedlings are not getting crowded; separate them if it looks like they are running out of room.  What looked like plenty of space at the beginning of the growing cycle can turn into not enough space as the plants get taller and wider.

Keep the small fan running on them if you have one. Otherwise stimulate the plants by lightly running your hand over the tops of the leaves a couple of times a day. The movement provided by the fan or your hand  helps to strengthen the plants.

As garden transplanting time approaches, you need to begin to “harden-off” (or “harden”) your plants. For weeks they have been inside in a safe and balmy environment.  If you suddenly remove them from their indoor spot and plant them directly into the garden, they could die (or at the very least be set back in their development) from the exposure to direct sunlight and cool night time temperatures.  Hardening-off minimizes this stress.

Keep in mind that different plants are set out into the garden at different times.  Some can tolerate a light frost so can be set out a week or two before the last frost of spring these include: lettuce, cabbage, broccoli,beets, onions, and spinach. A couple of cold tolerant flowers come to mind, Sweet William and Lupine.  Most of the rest of our annual garden plants are considered to be warm season crops and so can’t be set out until after the last frost of the season.

Most annuals need to be transplanted after the danger of frost.

The hardening-off  process starts by changing the indoor growing conditions.  About two weeks before you plan on setting out the plants into the garden, lower the growing temperature and cut back on your watering. Stop fertilizing too.

After about a week of indoor treatment, move your plants outside to a protected area out of the wind,  the east side of a house works well especially if you can’t be home to move them when needed.  On the east side of a house the plants can get the morning sun and are shaded by the time the harshest sunlight occurs in the afternoon.

On the first day, leave them out for only an hour; then two hours the next day; then three hours.  After a few days leave them out for the entire morning. Eventually (after a week or so) they will be accustom to spending all of their time outside. It is at that point they can be moved into the garden.

Just as a reminder,  you to keep an eye out on the weather during the time you are getting your plants used to being outside.  If your plants should be exposed to a cold snap or severe storm, weeks of work could be lost.

There are a few more things that should be considered when the plants are transplanted into the garden.  We’ll discuss those in a later post as we get nearer to planting time.

Bob

Starting Seeds at Home VII

Friday, April 2nd, 2010

Once your seeds have germinated and have started to grow, you need to think about the next step in the process which is transplanting. Transplanting is the process of moving a plant from one location to another.  In this case we are moving the young seedling from its spot where it was sown in a flat or other container to its new container  where it will be left to grow big enough to be moved outside into the garden.

It is time to transplant when you see the first set of “true leaves” starting to grow on the seedlings. The true leaves usually look quite a bit different from the first set of leaves (cotyledons).

As in sowing seeds, your transplant container and soil should both be clean.  The soil you use can be coarser than the soil the seed was sown into.  Moisten the soil mix before transplanting.

Using a spoon, knife or other tool gently lift the seedlings from the soil.  If you end up with a bunch of seedlings stuck together, separate them by gingerly teasing the roots apart.

Always handle seedlings by their leaves and roots; avoid crushing the stem.

Always handle transplants by their leaves and roots, not by their stems.

Make a hole into the soil of the container receiving the transplant and place the seedling into the new soil mix. Try to keep the roots from curving upward if you can.  A slim stick or similar tool can be used to guide the roots into the  soil.

Use a tool to form a hole in the soil mix.

Then very gently tuck the soil around the roots.

The soil mix is gently tucked around the roots.

Water the seedlings using a watering can with a very fine stream or, if the seedlings are small, set the container into a pan of water and let the moisture wick up from the bottom.  Let the excess water drain away.

At this stage most seedlings will not need to be covered with plastic.  Place the newly transplanted seedlings back under the grow lights or in a sunny window.  Keep an eye out  for signs of low light; these include elongation of the stems and/or leaning toward the light source. Raise or lower your grow lights as needed to keep the plants within two to three inches of the fluorescent tubes.

Continued use of a small fan to direct air over the plants is still a good idea at this stage.

Maintain  your water and fertilizer schedule as before.

When the transplants get big enough, they can be moved out into the garden.  Before that happens however, they need to go through one more step. We’ll discuss that in the next post.

Bob

Starting Seeds at Home VI

Monday, March 29th, 2010

If  you have sown your seeds correctly and placed them in a warm area, they should germinate and emerge from the soil  within a few days.

Take your germinated seeds off of the heating mat and get them into some bright  light. Your heat mat can be now used to start the next batch of seeds.

Not all of us have access to a greenhouse or a sun room to grow our newly emerged seedlings.  A bright, sunny window with a southern exposure works almost as well.  The other alternative is to place the seedlings under florescent lights. Two 40 watt fluorescent tubes  will provide all the light your baby plants need.  Special “grow lights” or “full spectrum” are really not necessary just use an ordinary shop light.  The trick is to make sure the seedlings are about 2 inches from the lights, certainly not more than 3 inches.

Use an ordinary shop light for your growing seedlings

The young plants need only about 15 to 16 hours of light a day.  They must have a dark period in order to grow properly.

Direct the air from a small fan onto your growing seedlings.  The movement caused by this small amount of air helps strengthen the young plants and helps prevent fungus from infecting them.

If you notice that your plants are getting “lanky”, top heavy, or lean toward the light, then you know they are not getting enough light, so make the necessary corrections to improve the lighting conditions.  Often they will get so top heavy that they will fall over.  If this happens, transplant them into another container at a deeper depth.  Many times you can salvage your seedlings in this manner.

Fluorescent tubes do give off some heat. This heat combined with the fan may tend to dry out the potting mix a little so be sure to check on your seedlings a couple of times a day…they are babies after all!

As your seedlings start to grow, keep an eye out for a problem called “damping off”.  It is disheartening to get to the point where the seeds are up and growing fine only to find one morning that the plants have fallen over and are starting to die.

Damping off is caused by a fungus that usually infects the seedlings’ stems right at the soil line.  You will notice that the stem of the seedling is shriveled. The plant cannot recover at this point. The most common cause is using potting containers that were not properly cleaned or using seeding mix that was not sterilized. Lack of air movement and soggy soil can also make the problem worse.

Fertilize your seedling every other watering or so with a diluted half-strength solution of soluble plant fertilizer. Use distilled or RO water for your seedlings. Chlorine from city water can damage them.  If you don’t have access to distilled water, leave a potful of tap water out overnight to let the chlorine “gas off”.  Placing the growing container in water and letting it soak up from the bottom will help keep your seedlings from being knocked over by a stream of water from the watering can.

Eventually your seedlings will need to be transplanted. We’ll discuss that and other things in the next post.

Bob

Starting Seeds at Home V

Wednesday, March 24th, 2010

There are two schools of thought on how to best fill containers for starting seeds.

One idea is to fill the flat with dry soil mix and then moisten it by watering it from the top with a sprinkling can; or you can set the flat into a pan of water and let it wick up into the mix.  Both ways are fine although watering from the top is often quicker if you need to get it moist in a hurry for some reason.  The overhead water also packs down the soil mix slightly making it somewhat denser.

The second idea is to moisten the soil mix before placing it into the pot.  This is done by adding water to the mix either directly into it’s original bag or by moistening only part of it in a bucket or tub.  It’s easy to over-do the watering and end up with a water-logged soil mix which then has to be allowed to drain before using.

If you are using starting mix that you have moistened ahead of time, scoop up some mix and place it into the flat or pot and level it off.  Then lightly bump the tray on the table top once or twice to settle in the mix.  Resist the urge to pack the soil into the container with your fingers, that will reduce the needed air space in the soil.  Remember, it’s  not like making sand castles!

Different seeds have different germination requirements.  Some need a cold period, some need to be soaked, some need to be treated with growth hormones, some even need to pass through the digestive tract of an animal! We won’t worry about any of those types of seeds in this discussion, for now we’ll stick to the most common requirements.

The most important thing you need to know is whether or not the seed requires light to germinate.  Generally speaking, the larger seeds can be covered while the very tiny seeds need to be sown on top of the mix.  Check the seed packet to be sure.

Seeds that need to be covered should be placed about 2 or 3 times their diameter below the soil.  While small surface sown seeds should  be lightly pressed into the top of the mix so the seed makes good contact with the soil.

You can choose to sow your seeds into rows in the container, in which case you will need to transplant them later. Or you can sow two or three seeds per cell in your flat (or pot).  Later you will save the strongest seedling and discard the others.

As a guide, sow large seeds about an inch apart; medium seeds about 1/2″ to 3/8″ apart; and tiny seeds about 1/4″ apart.

Since germinating seeds need high humidity,  cover your container with clear plastic of some sort.  Be sure to keep the plastic propped up off of the surface of the soil.  For greenhouse flats, clear plastic “domes” are available.

Put your newly planted container in a warm spot to hasten germination. Placing them on a seed starting heat mat is ideal. These electric mats usually come with a built in thermostat to keep your tray at the ideal temperature for germinating most garden seeds.

Heat mats for seeds are readily available at garden centers.

Some seeds will emerge from the soil within a day or two while others take longer.  After they are up, they need to be cared for, we’ll discuss how to do that and how to avoid potential problems in part six of our series.

Bob

Starting Seeds at Home IV

Monday, March 22nd, 2010

Gardeners can be quite resourceful when it comes to finding containers to use for starting their seeds.

If you have purchased plants from a greenhouse in the past, you are familiar with a black thermoformed plastic tray called the greenhouse “flat”.  These typically measure about 11″x21″ by 2-1/2″ deep .

The flat in turn has a black plastic liner or “insert” placed into it. The inserts are commonly divided into sections ranging  from 24 to 72 “cells”.

This system of greenhouse flats works wonderfully for use in the greenhouse because all of the starting and growing containers are standardized and easy to handle.

Flats are also available for use at home, either at well stocked garden centers, on-line, or through gardening catalogs. They work just as well at home as in the greenhouse if all of your seeds require the same growing conditions.

Back in the old days, greenhouse people used to make their flats out of untreated wood. A typical size was 16″x24″x3″. This is still a good option for some gardeners.

If you only have a few seeds of each variety and they have widely different sowing and growing conditions, then a flat might not work for you. Several smaller containers must be used to accommodate the different seed requirements.

This is where you can use your imagination to find containers in which to start your seeds.  Most commonly you see folks using recycled milk cartons or jugs cut to size.  With today’s over-packaging of food products, we have a huge selection from which to choose. Previous generations didn’t have this wide variety of choices.

Look around in the trash and you can find yogurt cups, egg cartons, snack containers, frozen food packaging, fast food packaging and more; all of which has potential to be recycled for use in starting seeds.

Whatever you decide to use for your container, it absolutely must have drainage holes. Cut or punch out several holes in the bottom to allow excess water to drain away.

You can use newspaper to make your own paper pots.  Cut the newspaper into 3-1/2″ wide strips and wrap them around a glass jar a couple of times. Tape the paper where it overlaps and fold the bottom of the paper to make the pot bottom.

Since I’m a “saver” type of guy, I like to save my plastic flats, liners and pots from season to season. Many people say they don’t like plastic pots because they don’t degrade in the land fill. I say that’s their best attribute, the plastic holds up well from year to year and can be re-used. Just don’t be in such a hurry to throw them away every year.

Some of last year's greenhouse flats waiting to be washed, disinfected and re-used.

When re-using pots, make sure they are washed to get off all of last year’s soil. Then sterilize then by using a 10% bleach solution:1 part bleach to 9 parts water. If you don’t thoroughly clean them, you run the risk of transferring disease to your seedlings.

Common garden soil cannot be used to start seeds indoors no matter how good it grows crops outside. Soil dug from the garden is just too dense and will form a hard mass in the container making it extremely difficult for the plants to grow.

Seedlings need a soil that is able to hold water, yet can still drain away excess moisture. The roots also need a certain amount of air in order to grow properly. Some gardeners try to blend their own starting mixes but this is not recommended for beginners.

The soil that is used to fill your containers must be sterilized for the same reason you sterilize the pots: disease prevention.

To get all of the characteristics of a good seed starting soil, it is easiest to purchase a bag of packaged seed starting mix. These have already been sterilized by the manufacturer.  Be sure the mix is labeled as a seed starting blend and not a potting mix.  Potting mix is usually to coarse for starting all but the largest seeds.

In the next blog we’ll discuss filling your containers and sowing your seeds.

Bob

Starting Seeds at Home III

Saturday, March 20th, 2010

“Timing is everything”.  We’ve all heard that from people ranging from comedians to investment advisers; it is also true when starting seeds at home.

If seeds are started too early, the seedlings you are trying to raise will out-grow their space before you have a chance to transplant them out into the garden.  On the other hand, if you start them too late, well, you might as well have saved yourself all of the trouble and sowed the seeds outside directly into the garden.

The timing revolves around the weather, specifically the last frost of spring, also known as the “frost free date”.

Climatologists and weathermen being the scientists they are,  have very specific dates dealing with specific spring temperatures.  For our purposes in the garden, we shoot for Mid May as our date.  There still is a fair chance of  some chilly temperatures at that date but not  too much of a chance of an actual freeze happening.

The other factor to consider in your timing is whether you are sowing what I like to call ‘warm season’ crops or ‘cool season’ plants.

Vegetable plants such as  onion, lettuce, and cabbage family (which includes cauliflower, broccoli, brussels sprouts and others) are considered cool season plants and are tolerant of freezing temperatures to a certain extent.

Flowers such as pansy, snapdragon, alyssum, sweet peas and others are cool season plants as well.

Most other annuals can be considered warm season plants for our discussion here.

The cool season plants can be transplanted into the garden as early as four or five weeks before the frost date. The warm season plants will never survive in those cold conditions and need to be set out into the garden after the soil has warmed up and there is no chance for frost, usually late May.

Right now we are in the beginning of the main part of seed starting season. During the next week or two you need to get some of your seeds started. Tomatoes and peppers should  be started soon because they take so long to get to a size that can be transplanted into the garden.  Cabbage takes less time to get to transplanting size but remember, they can be set out much earlier.

Often seed packets give you suggestions on when to sow the contents.

Some seed companies include very detailed sowing instructions on their packets.

Next time we’ll discuss soil mix and containers for your seeds.

Bob

Starting Seeds at Home II

Thursday, March 18th, 2010

During the seed starting class, some participants confided in me that they had tried seed starting in the past but were frustrated by the lack of success.

My suggestion is to start out with the easier seeds in order to gain experience and confidence before moving on to the more exotic seeds.

Some easiest  vegetable seeds are the cabbage family, which in addition to cabbage, includes broccoli, cauliflower and brussels sprouts.

Onions, head lettuce, tomatoes and peppers are also considered easy to start.

You can gain some valuable experience starting flowers such as alyssum, cosmos, marigold and zinnia. This may seem like a short list, but there are a wide variety of shapes colors and sizes of these varieties available now days.

I would also venture to say that nearly all seed varieties  available from a hardware or department store would fall into the category of easy to start. This is because the seed companies also want you to have a good gardening experience, so they offer the seeds which are most likely to grow in the hands of a beginner.

Different varieties of seeds need to be started at different times so we’ll cover that in the next blog.

Bob

Starting Seeds at Home

Tuesday, March 16th, 2010

This past Saturday Judy and I taught a two hour class at the University of Michigan‘s Matthaei Botanical Gardens on the topic of starting seeds at home. We covered a lot of information during the class but two hours wasn’t nearly enough time considering the subject of seeds and seeding would be covered in one or two semesters if you were to attend an agricultural college.

Our participant’s experience covered a wide gamut from those who never attempted it to those with a fair amount of success.

About half of the class was interested in growing  flowers while the other half vegetables.  Although the primary discussion was about starting annual plants, we did touch on perennials briefly.

We spent the first hour in a classroom going over many of the basics.  During the second hour we moved into the greenhouse and actually sowed seeds and transplanted seedlings.  A couple of the participants weren’t really prepared to get their hands into the dirt but happily joined in anyway.

Since the class was such a success, we plan on holding it again next year.

If you are interested in starting your own plants from seed, follow along here at All Things Green for most of the information we presented in the class.

In the next post we’ll  get into some things to consider before you begin sowing your seeds.

Bob