Growing Pepper Seedlings

Pepper seedlings are among the hardest vegetable plants to grow, and some hot peppers are even more difficult than the sweet peppers.

Seeds should be planted at least 8 weeks before the ALFD (average last frost date) in your immediate area. And you should not transplant the seedlings into your garden until after the ALFD.

Use a soil mixture of 65% sawdust and 35% sand. Peat moss, perlite, Coconut husks, rice hulls, coffee hulls, or pine needles can substitute for the sawdust, alone or in any combination.

The Mittleider Magic Pre-Plant mix should be mixed with the growing medium before planting seed – at 1 1/2 oz (3 tablespoons) per cubic foot of soil – then NO fertilizer should be applied until after the seedlings emerge. Water with plain water and keep the soil moist, but not soaking wet.

If you’re only growing a few plants place the seeds 2″ apart in a seedling flat. For hundreds or thousands of plants place 100-125 seeds per row in 1/4″-deep furrows 2″ apart in a tray.

Cover the tray with burlap to avoid moving the seeds as you water.

Keep the planting soil-mix moist and maintain temperatures between 75 and 85 degrees Fahrenheit. No light is best until the seeds show above the soil, then immediate sunlight is needed for 8-12 hours each day, to prevent the stem from “stretching” to seek adequate light.

If you can’t give the seedlings direct sunlight you must provide grow-lights within 1″ of the plant leaves for 16+ hours per day. Two Fluorescent lights – one warm and one cool – work well.

Again, constant temperatures should be maintained in the 75-85 range.

A Constant Feed solution of 16 ounces Weekly Feed mix to 55 gallons of water (a scant 1 ounce per 3 gallons water) should be used for watering the seedlings immediately after emergence.

Seedlings should be transplanted 2″ – 2 1/2″ apart by the time they get their second set of true leaves. The soil for this transplant should contain both Pre-Plant mix at 1 1/2 oz and Weekly Feed mix at 3/4 oz per cubic foot of soil mix.

Peppers grow slowly and need warm temperatures to do well. They will also require a few days to recover from the transplant, so don’t be discouraged if they are still small after 3-4 weeks.

Before transplanting to the garden take seedlings outside onto tables in full sun for 2 to 3 days, to “harden them off”, or acclimatize them to the outside growing conditions. If the nights get very cold bring the plants back inside.

Some protection may also be needed after the seedlings are in the garden. Mini-greenhouses made with greenhouse plastic over arched PVC frames will keep cold winds off the plants and allow the sun to warm the soil much faster.

Remove the covers when outside temperatures approach 70 degrees, and make sure that temperatures in the beds do not exceed 80-85 degrees. Some air flow during the daytime is important.

Germinating Peppers & Tomatoes – How Long?

Q.  What conditions are necessary for germinating my pepper and tomato seeds?  How long will it take?

A.  Peppers, tomatoes, and eggplant like the soil temperatures to be at
least 75 degrees fahrenheit, and they will germinate much faster in the low to mid 80’s.  Tomatoes can germinate in less than a week under ideal conditions, and peppers are a little slower.  Don’t get them too hot, however, or you’ll lose more than you want to.

The thing that most often causes peppers, tomatoes, and other seeds to take a long time germinating is too-cold temperatures.

Moisture is also important, but don’t leave them in standing water or you’ll drown them.

Store your seeds in a cool, dark, and dry place.  Seed will lose its viability very fast in warm, and especially humid conditions.  Cool and dry are essential for long-term storage of your seeds.

Jim Kennard

Grow Your Own Seedlings – But Pay Attention To The Details!!

Q.  I was asked to look at a greenhouse full of seedlings that were not growing, and in various stages of dying, in the hopes that I could save the crop.  Here’s what I found was wrong – for starters.

A.  The trays or flats were built with no drainage.  Number one No-No!  Plants must have oxygen, and will drown without proper drainage, or at the very least there will be a build-up of salinity, which will totally stop them from growing.

The soil medium was more like clay soil than the soft and fluffy sawdust, peatmoss, and perlite that we recommend.  Even though sawdust and sand were being used, the sawdust was truly DUST and the sand was finer even than masonry sand.  In addition, they were pressed down firmly before planting.  We recommend coarser materials than that – again for the oxygen and drainage.

Pre-Plant and Weekly Feed fertilizers were not applied properly.  They needed 1/2 again the amount they had been given.  For a flat 18″ square (1/2 meter) 1 1/2 ounces Pre-Plant and 3/4 ounce of Weekly Feed should be applied and worked into the soil before transplanting.

The plants were planted too close together.  This means more plants are sharing the same amount of air, light, water, and fertilizer.  Most plants should not be planted closer than 64 in a 1/2-meter square flat.  The ones I saw were all planted 81 per tray.

The flats were also very shallow, which would become a problem soon, if the plants happen to live.  Plant roots need room, and a flat should be 2 3/4″–3″ deep.

Almost all plants were exhibiting deficiency symptoms of at least one nutrient, and I believe several were needed.  Purple leaves indicate a phosphorus deficiency, and these needed that plus magnesium, and probably calcium (the major nutrient in the Pre-Plant Mix).

I began by drilling 32 1 cm holes in each flat, and applied Pre-Plant and Weekly Feed  sufficient to correct the original deficiency.  I next aerated 200+ flats 1″ deep by dragging a dibble beside every row in both directions.  I then applied the other two nutrients I felt were needed immediately by including them in the first watering.

It would be very time-consuming, costly, and stressful to the plants to transplant them into better soil medium.  And I could not tell if the holes were sufficient to solve the drainage problem – I suspect they were not, mostly because of the soil medium being much too dense.  Sadly I had to leave more than 15,000 vegetable plants to their fate, in the hands of people who know next to nothing about their proper care. 

I recommend anyone who is interested in growing their own seedlings, which is very rewarding on several levels, should get the Mittleider Gardening Library CD, which is available at in the Store section, and study Let’s Grow Tomatoes and Gardening ByThey Foot for starters.

Mistakes to Avoid & How to Do it Right

Common mistakes in growing seedlings include:

1) Not maintaining even temperatures between 70+ and 80+ degrees fahrenheit during seed germination, emergence, and formation of first true leaves.

2) Not giving the seedlings full sunlight immediately upon emergence and all day thereafter – or if using grow-lights at least 16 hours of light each day.

3) Not feeding plants properly, which means a) having Pre-Plant Mix in the soil mix before planting seed, b)  using only water until plants emerge from the soil, and c) watering with the Constant-Feed solution immediately upon emergence of your plants.  The constant-feed solution is a mixture of 1 ounce (2 tablespoons) of Weekly Feed in 3 gallons of water.

If you are growing the seedlings inside your house, if it’s not warm, put a double fluorescent tube, with one cool and one warm, 1″ or closer to the plant leaves, and leave the lights on at least 16 hours per day.  And the soil needs to be warm for the seeds to germinate.  Buying an electric seed germination mat will improve your  germination.

Growing Seedlings When it’s Too Cold to Heat the Greenhouse

If you are using an exterior seedhouse and it’s cold, build a small second
covering on one of the tables, then place a small electric heater beneath it.  That way, rather than trying to heat a large greenhouse in cold weather, you’re only heating the small area for a few flats of new seedlings.

A seed flat can hold 400-800 new seedlings, and for that first critical 2-3 weeks during germination, emergence, and formation of their first true leaves they must have uniform warm temperatures – but they take up very little space. They also don’t need light until they emerge from the soil, but then they need maximum light IMMEDIATELY.

Do your first transplanting when they have their 2nd set of true leaves.  Then you will need 10 times the number of flats you started with.  It’s usually a bit warmer by then, plus the seedlings can handle cooler weather than germinating seedlings, so with a little heat at nights you can usually make it.

If you are starting seedlings in your house, unless it’s being done in a room with temperatures in the 70’s, the soil may be too cold for good germination.  An electric germination mat will keep flats warm, and costs $30 for a single flat size and $70 for a 4-flat size at  You usually only have to use it until the plants are established – then they can put up with somewhat cooler roots. 

But remember that plants need at least 60 degrees fahrenheit in order to grow, and most of them go dormant at 50 degrees – especially the warm weather ones – so maintaining warm temperatures continues to be very important, especially in the daytime.

Pruning Seedlings to Grow Healthy, Sturdy Plants – Fast

Your goal when growing seedlings is to make them as strong and
sturdy as possible, and do it as quickly as possible.

Excellent instructions for growing healthy seedlings are contained
in Let’s Grow Tomatoes pages 51-53 and Grow-Bed Gardening pages 86 – 92, and Grow-Bed Gardening has many pictures illustrating the

Regrettably, both these books are temporarily not available in hard
copy, as we have sold out the most recent editions.  We hope to soon
have them both available for download on the website.  Both books
are contained in the Gardening Library CD, which I highly recommend.

Meanwhile, here is what Let’s Grow Tomatoes says about pruning
leaves to keep the plant stems from becoming spindly, with
parenthetical comments added by me:

“When the leaves begin to overlap the leaves of other plants, the
experienced grower who insists on thick-stem plants prunes off the
leaves which overlap (carefully pinch them off with your
finger and thumb).  Pruning off the leaves increases the light
around the plant stems, and does not stop the growing tip from
growing (NEVER take off the growing tip, and always leave 2 or 3
leaves!  You can even take off a partial leaf.).  Pruning off the
leaves temporarily stops the upward growth of the plants, and
encourages the stems to thicken, which is what the grower desires.

“During this temporary period of reduced growth in the plant, the
grower has two choices:
1. to wait 7 to 10 days for new leaves to grow and overlap again and
pinch as before,
2. or, he can shift the plants into larger pots or gallon-size

“In the first choice the leaves must be pruned off again at the
proper time to keep the plants from getting spindly (because the
stems quickly become tall, thin, and weak as the plant stretches
looking for light), using the same procedure as explained earlier.

“In the second choice, shifting the plants into larger containers
provides more space between plants, delays pruning until a later
date, and encourages the stems to thicken – due to increased light
and circulation around the stems.

“If, therefore, space is available in the seedhouse to accommodate
larger containers, it is recommended that the plants be shifted from
the smaller pots into 4-inch pots or gallon containers before they
are pruned the second time.”

After 2 prunings, it is recommended that the pots be physically
separated to provide light to each plant, rather than continuing to

Jim Kennard

Growing Seedlings in the House – Problems in Transferring to the Garden

Q.  Why are my kitchen-window-grown plants so weak?  On taking them outside they turn yellow, burn, and many die the first day.
A.  The whole reason for growing plants early – in the house or greenhouse – is to give them a headstart under good growing conditions.  The key to success, however, is accomplishing the good growing conditions.
Many times folks think they can stick seeds in some dirt in the kitchen window, and because there is some sunlight the plants will grow and thrive, and be healthy and robust when it’s time to go outside.  And because so few of us know how to feed plants, we often also fail to feed them in our kitchen-window pots.  These practices are a sure recipe for failure, rather than success.
Dirt is just as difficult for sprouting seeds to penetrate in your kitchen window as it is in the garden, and so it’s common for people to have 50% or less of their plants even see the light of day.  Never use dirt in seedling production.  Use a light and clean growing medium consisting of sawdust and sand, or other similar elements, such as peat moss or perlite.  The sand should be 25 to 35% by volume, and equal amounts of at least two others is ideal.
And our windows are often quite cold and drafty – not the ideal warm and secure nurseries our new plant babies need.  Use a thermometer and make certain the soil temperatures stay in the range of 70-80 degrees fahrenheit.  A heat pad with thermostat is inexpensive and accurate, and will pay for itself quickly.
With no regular feeding all babies experience a high mortality rate.  A very dilute fertilizer solution similar to the Miracle Grow regimen is very good.  We recommend regular watering with a Constant Feed solution consisting of 1 ounce of Mittleider Magic Weekly Feed in 3 gallons of water.
Sunlight all day long immediately after emergence is also essential.  If you can’t give the real thing, you must replicate it as closely as possible with fluorescent tubes for at least 16 hours per day.  Anything less won’t do the job, and you’re better off not wasting your time and the valuable seeds.

Taking House-Grown Seedlings Outside – Problems

Q.  My tomatoes, peppers, cucumbers, and cabbage are dying only hours after taking them outside!  What have I done wrong?  The room they were in has a West-facing window, so they received 2-3 hours of sun on sunny days.  I put fertilizer in the potting soil, but did not feed them after that. 
A.  It is so important that plants receive full sun for 8+ hours per day from the moment they poke their heads above ground.  Lacking actual sunlight, they have to have a warm and cool fluorescent tube placed about 1″ from the surface of the plants for 16 + hours per day.
Failure to give your plants adequate light in the house made them very susceptible to burning up in the heat and light of the full sun.
They were also very weak from lack of food, which also made them unable to handle the stress of a changed environment.  ALWAYS water your new seedlings with the Constant Feed solution of 1 ounce Mittleider Magic Weekly Feed in 3 gallons of water, and they will be healthy and strong, and much more able to handle the shock of hardening off and transplanting.  And of course they will be much bigger also.
How about pruning.  You also must keep them pruned so the leaves do not overlap.  This creats small shocks, and gets the plant to grow a stronger, thicker stem – also preparing it for the harsh reality of the outdoors.
I suggest a good nursery, to get you some healthy plants, so you don’t lose the season.  The ones you describe will not recover, and will never produce a god crop.

Using Grow-Lights

Q.  I read  that if you leave your light source only about 6 or 7 inches above your plants it will help defeat them getting leggy, is this right?  The problem is that I feel the plant light I have over them right now may be too strong, and that I might burn them, so should I get a less bright bulb?

A.  Unless the light bulb feels warm to your hand from 3-4″ away, you have no
danger of burning the plants.  You should have 2 – 4-foot 40 watt fluorescent tubes – one warm white and the other cool white.   Place them within 1-2″ of the plants.  They can’t get too much light, and those 40 watt tubes won’t burn them.  6″ is definitely too far away, and the plants WiLL stretch.

Remember to give your plants full light as soon as you first see any sprouts showing above the soil surface.  Any delay at all, and the plants will develop long, skinny, weak stems as they search for that all-important light.

Feeding is also essential as soon as the plants are up.  Use the “Constant Feed” solution of 1 ounce (two tablespoons) of Mittleider Magic Weekly Feed mix thoroughly mixed with 3 gallons of water.  Water with this solution every time you water, which should be every day at least.

Using Wall-O-Waters, etc. for starting seedlings

Q.  I saw something on Joy in the Garden (a Salt Lake TV show) that says you can plant tomato seedlings in a Wall O Waters now, and have very early tomatos. She said that when water freezes it gives off heat, and this is what
protects the little plants.

Has anyone tried this?  It isn’t REAL cold at night, but it is getting into the low 20s.  I have three Wall O Waters, and will plant some seeds to try to get something going if it seems reasonable.

A.  Do not count on Wall-O-Waters, or anything else out in the garden, to sprout your vegetable seeds and get them going!  Nature has dictated that seeds need consistent warm temperatures to sprout, and so you need a greenhouse, light box, or light table, etc. to do that effectively and get healthy vigorous plants.

So far as using Wall-O-Waters for protecting tomatoes, etc. from freezing, I would not count on them to help you below about 30 degrees fahrenheit.  You will be much better served to keep your plants in a warm environment with plenty of direct sunlight until the danger of hard frosts is past – and why take them out even then if you have room for them in the protected environment?  Your plants will be dormant at temperatures below 50+ degrees, and will likely be slowed more than helped by taking them to the garden too early.
Some folks think having them in the soil early acclimates them and makes them more sturdy.  Dr. Mittleider says you need only 2-3 days to “harden-off” your plants outside before planting them, and they will do just great, assuming the weather in the garden is warm enough for them to grow. 
If you will grow your plants under ideal conditions, you can gain a 4-6 week advantage over planting in the garden early, and thus have a much longer harvest season, with ripe tomatoes by the first of July in Utah and similar climates.
Jim Kennard