Container Gardening Secret Sauce

Container Gardening Secret Sauce

 Spring is my favorite time of year! I love traveling to our local greenhouses and seeing all of the beautiful plants available to decorate my yard, porch and deck. We have lots of choices here In SE PA since we are in Amish country and in addition to the commercial greenhouses lots of farms have plants for sale at roadside stands.

One of Our Local Farm Markets

Mother’s Day is classically seen as our ‘Frost Free’ date here so I’m always really excited  at this time of year to get those plants home and into hanging planters, pots and window boxes. In the past, my excitement would wane with the heat of summer. I felt that I could not keep up with the watering and my plants suffered with my busy schedule. But one of my Master Gardener friends shared her secrets to keeping her containers looking good all summer. I’ve added to her suggestions over the years to come up my own recipe for success and I’m going to share those with you!

First, choose the right plants for the right spot. If you aren’t sure how to do this, see my previous post here.

Second, make sure you choose well drained containers. All of my containers have drainage holes at the bottom like the one shown below. If plants sit in soggy soil for too long, the roots will rot.

I also cover those holes with landscape fabric to keep the potting mix in and allow the water to drain. See below.

EXTRA TIP: For larger containers, I keep the weight down and save on potting mix by filling the bottom of the pot with empty plastic cell pots that plants came in. See below.

Now that you have the right plants and have your pots prepared, it’s time to prepare your potting mix.

Potting soil and potting mixes go by lots of names on the bags. For containers its best to use a sterile mix that does not contain soil. If the bag contains soil it is meant for flower beds or filling in spots in the lawn. Soilless mixes don’t contain soil but rather peat or coir, pine bark, and vermiculite or perlite. These combinations don’t provide any nutrients but rather provide a sterile, light, well-draining environment that container plants need to get started. And going forward potting mix does not compact the way soil will, thus continuing to provide good drainage and giving the roots the access to oxygen that they need. Many bags of commercially available potting mixes also contain fertilizers and water retaining crystals. Check the labels to be sure what you are getting is soilless.

I like to make my own 'secret sauce' and I'm going to share that recipe with you now!

First I start out with a bale of promix just like the nurseries use. I buy so much because I do so many pots in a season and I have room to store the leftover mix in my shed for the next season. Here is a photo of the kind I buy:

If you are not doing a large number of pots you can buy the potting mix by the bag at your local greenhouse or garden center.

I also purchase slow release fertilizer list Osmocote

water retaining crystals like SoilMoist

and a general purpose fertilizer like MiracleGrow.

The Osmocote will deliver small amounts of fertilizer to your plants throughout the next few months. The water retaining crystals hold water and deliver it slowly to the roots of the plants. This is my #1 secret for reducing your maintenance of your containers.

I like to hydrate the crystals before using them so I take a clean container and put some of the crystals in the bottom. Start small until you get a feel for how much you have after you hydrate the crystals. You don’t want to overdue the crystals. I did overdue things one year thinking more was better – and then we had a very rainy summer so there was too much water being held in my containers and my plants started to rot.

Here are the crystals before adding water:

and then after they are hydrated. 

While you are waiting for the crystals to hydrate, scoop some of you your potting mix into a container. You can use a bowl, bucket, trug, or wheelbarrow depending on how many pots you are doing. Wet the grow mix, mix with a trowel and then wet again if needed. You will find that you need to keep mixing to get the water to moisten the all of the mix. Kind of like cake mix. You want the mix to be moist, not soggy.


Next add the slow release fertilizer according to the package directions.

Finally, add the SoilMoist after the crystals are fully hydrated. You should see them throughout the mix but not on top of each other. Mix all of this very well.

Now that you have your potting mixture prepared, it’s time to prepare your plants. Take another bucket and add water and dissolve an all-purpose fertilizer like MiracleGrow according to the package directions. 

I just used a bucket with gallon markings that I got from a local home store and only partially filled it. You will see why in just a moment.

Next you are going to take the plants you are about to plant and ‘dunk them’ as my Master Gardener friend would say. Do not fully submerge them. You are going to submerge the pots only. The plant should be above water. Then wait until the air bubbles stop escaping from the pots. Doing this fully hydrates plants that may be dry from being in the greenhouse and gives them a shot of fertilizer to help them get established and off to a good start.

Now you are finally ready to plant. Scoop some of your mixture into your container.

Remove your plants from the pots and cells packs and place them in your container.

Add soil around all of the plants up to the base of the plants.

Finally, mist the container with your hose to be sure the plants are well-hydrated and to wash off any of the fertilizer mix that may have gotten on the leaves of the plants.

If any of the plants have spent blooms or are too leggy, trim off the spent blooms and trim back the leggy parts. I always find this the hardest thing to do, but this does give the plant a chance to concentrate its energy on filling out rather than extending the leggy parts.

To keep your plants looking great, water when the soil gets dry. The water retaining crystals should let you decrease your watering chores. Be sure to check the soil before watering so that you don’t overwater.

About once per month water with the all-purpose fertilizer to give the plants a boost. You can also add more slow release fertilizer to the top of the soil about half-way through the growing season.

Finally make sure to remove spent blooms regularly ( called deadheading) as this give the plant the energy to make more flowers.

I hope this helps you to create beautiful container gardens that last all summer long!

 Happy Gardening and Relaxing!




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