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Start Your Vegetable Seeds Indoors with the Right Soil, Fertilizer, Moisture,Temperature & Sunlight.

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I’m a week late getting this essential information on seed starting to you. I want to apologize for that up front and hope today’s suggestions get to you in time to be of benefit. My last post emphasized the importance of starting your seeds at the right time and I included a seed starting calendar for reference. I also presented both sides of the debate on starting seeds versus buying transplants. If you read it, I’m sure my bias toward seed starting was apparent.

Do Your Seedlings a Favor

Use a High Quality Germinating Mix

The germinating mix you use is important and not all brands have the same composition. Here are the essential ingredients you’ll want to look for when reading the label on the bag. You want your mix to be light with good moisture retention, but one that drains well. Better mixes contain mycorrhizae fungi which penetrate the cells of the roots of vascular plants and help capture nutrients like phosphorus and micronutrients from the soil. This is a very important function in growing healthy plants that produce more vegetables, fruit and flowers.

  • Sphagnum peat moss
  • Peat humus
  • Perlite
  • Dolomitic limestone
  • Mycorrhizae fungi (root stimulator)

I’ve used two different germinating mixes over the past few years with equal success. You won’t go wrong with either.

  • Light Warrior Seed Starter
  • Espoma Organic Seed Starter

Fertilize Your Seedlings

With What and How Often

Several weeks ago I wrote extensively on fertilizing seedlings and transplants, so I’ll mention only the most important things you need to know here. Seeds don’t need fertilizer to germinate and grow their first set of leaves (cotyledons). The time to start fertilizing is when the next set of leaves has begun to appear. These are the first true leaves and are nourished by the roots and nutrients from the soil.

Fish emulsion (deodorized form) is my fertilizer of choice and I begin the weekly applications as soon as I see the first set of “true” leaves appear. As a rule of thumb, I mix the fish emulsion into the water at ¼ the recommended rate for the first three weeks. I increase the solution to ½ the recommended rate for the 4th week. By the 6th week, I’m fertilizing with fish emulsion at the recommended rate. Follow the instructions on the bottle. For most brands its 1 tbs. per gallon. Consistent applications must be continued for the full life of the plants.

Are Heat Mats Required?

The majority of vegetable and flower seed germinate best when the soil temperature is 65 – 70 degrees. The easiest way to accomplish this is to use heat mats. They are readily available at most garden centers and home centers. Keep them plugged in 24 hours a day for the first month. They draw very little current and are far less expensive than heating a room to 70 degrees day and night.

Watering Your Seedlings

How Much and How Often

Everyone you talk to have a trick or advice for watering newly sown seeds and seedlings and most work to some degree of success. My goals are,

  • To keep the growing medium consistently moist but not heavily saturated
  • Avoid floating the seeds to the surface or splashing them out of the seed tray
  • Water the seedlings without crushing them into the soil

These goals are easily met by watering from the bottom up. Before I make my case for bottom watering, I’ll share one technique to get started that everyone agrees on. Fully moisten the growing medium before your fill the pots and seed trays.

Most cell packs fit snugly in a plastic tray. They are constructed in a way to suspend the cell packs ¼” – ½” off the bottom of the tray. This will allow you to fill the tray with an inch of water before setting the cell packs in place. The growing mix will then wick up the water to the surface of newly planted seeds with no disruption of the seeds. You can continue with this method until it’s time to transplant into the My Garden Post planters. This technique works perfectly when fertilizing your seedlings.

I like using a mister to water, but it doesn’t take long to get tired from squeezing the grip and I’m never sure if I’ve misted enough to get water to the bottom of the cells. It’s easy to mist a tray of seedlings and find them dry and drooping within 12 hours.


How Much Light do Seedlings Need?

No light is necessary for seeds to germinate. Turn on the lights or place the seed tray in a bright window when the sprouts appear. Grow lights positioned 4” directly above the seedlings is the most effective method to provide all the light your plants need. T5 florescent bulbs are the fixture of choice for home gardeners. They are inexpensive to use and give off very little heat. I use a timer on my lights. They come on a 7 am and turn off at 7 pm. I never have to give it a thought.

If light fixtures are not in the budget, you’ll want to position your seed trays on a table or bench next to a large south facing window. This will require you to monitor your plants closely for moisture. The sun beaming through the glass will heat up and dry the soil faster than those under lights.

Assorted Seedlings Under T5 Florescent Lights

Assorted Seedlings Under T5 Florescent Lights

I think I’ve covered it all with this post and last.

  • Choose compact disease resistant varieties of vegetables, herbs and flowers for growing on your My Garden Post.
  • Start them at the right time inside so that they are sturdy and healthy when you move them outside after the threat of frost.
  • Use heat mats to insure a 70 degree germinating mix temperature for best germination.
  • Use a well-respected brand of germinating mix with the composition I described.
  • Fertilize with fish emulsion on a regular schedule.
  • Bottom water your plants whenever possible.

Please follow along next week. I plan to share all the reasons why My Garden Post is the preferred method of gardening for aging Americans, the disabled and all those living with a balcony, deck or patio.

Until then, thanks for following. Oliver

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