If plant growth in your garden has slowed, or your plants are looking puny, it might be time to side-dress your vegetable garden with fertilizer. What does that mean? Side dressing is applying additional fertilizer near your crop plants, either spread on the ground around them or in a little furrow a few inches away.
Side-dressing helps some crops more than others
Some crops will not need additional fertilizer in mid-summer to make a full harvest. These, mostly, are the beans and peas — Southern peas especially, like purple hull peas and zipper creams. Most of the other fruiting crops in a summer garden, like tomatoes, peppers, cucumbers, corn, eggplants, and squashes, may benefit from additional fertilizer. These crops are often referred to as medium feeders or heavy feeders. They have a higher need for some nutrients.
For plants that benefit from additional fertilizer in mid-summer, it usually is applied either when plants have begun to set their fruit (squash and cucumbers count as fruit, since they have seeds), or, for corn, when it is “knee high.” If your crops are further along than this, it is not too late to side-dress, if plant growth or productivity seems slow.
How to know if you need to side-dress your vegetable garden
These gardens are most likely to benefit from mid-summer side-dressing with fertilizer:
- Gardens with sandy or fast-draining soil
- Gardens that have received more than the usual amount of rain
- Gardens fertilized with water-soluble, conventional, chemical fertilizers
- Gardens that support a lot of medium and heavy feeders
In the first three examples, some of the nutrients added in spring may have washed away, out of reach of the plant roots. When nutrients are out of reach, plant growth will slow down, some plants may start to look a little pale, and harvests will not be as large as they should.
If the only plants in your garden that look pale/puny by mid-summer are the tomatoes, peppers, and/or eggplants, and all other crops are growing well, these crops might need a little extra magnesium. In my county, soils are low on magnesium. The tomato-family plants all have a slightly higher need for magnesium than other crops. This combination can result in plants that are pale and less productive.
To boost the available magnesium for these plants, use epsom salts. Dissolve a couple of tablespoons of epsom salts in two gallons of water, and pour it on the ground around your plants. Two tablespoons-full dissolved in two gallons of water should be enough for four plants. If the plants start to look darker green in about a week, then they needed the magnesium.
You also, of course, could get your soil tested through your local County Extension office. A soil lab report will tell you whether any nutrients are in short supply and offer a fertilizer recommendation. Extension fertilizer recommendations are, at this point, still all for conventional, chemical fertilizers, but even this can be helpful in pointing out the needs of your garden’s soil.
Some gardens may not need side-dressing
- Gardens with soil that is, essentially, all compost
- Gardens that are 100% beans and Southern peas that have been inoculated with bacteria that help fix nitrogen
If your garden soil is all-compost in a raised bed, and the compost was all new this spring, then the odds are good that your plants will not need side-dressing. Some community gardens in my county fill new beds with a product called “Soil3”, from SuperSod. This is an all-compost product. Soil3 and similar composts available in other areas can provide all the nutrients the garden plants will need for the first summer. Organic fertilizers may be needed in increasing amounts in later years.
Which organic fertilizer is good for side-dressing?
- The vegetable garden fertilizer you already have
- Fish emulsion or a seed-meal-based fertilizer
- Worm compost, yard compost, compost tea
If you have a complete garden fertilizer already, one that you used in spring, use that again in mid-summer, following directions on the container.
However, the nutrient that is most often in short-supply by mid-summer is nitrogen. It can leave your soil by going into the air in addition to being washed away. If you can locate a higher nitrogen fertilizer product like the Alaska fish emulsion fertilizer or the seed-meal-based Nature’s Source Garden Plant Food, those can be good choices.
Composts are also good choices. To side-dress with these, be sure to rake them in — shallowly to avoid damaging roots — around the plants, covering it all with soil. Then water the compost in well to give the soil bacteria, fungi, and other small life-forms better access, to start breaking it down for use by plants. Use a big shovelful of yard compost, or a cup or two of worm compost, per plant. Worm compost is usually a more concentrated source of nutrients than yard compost.
If you make compost tea from your compost, to pour around your plants, root-damage becomes a non-problem. The tea may need to be poured around the plants more often than just once in mid-summer, for best effect. Compost tea applied to leaves can also slow down the growth of fungal leaf diseases. (Compost tea recipe is in the “treating mildews” section of the Summer Squash blog post.)
For gardens prone to leaf disease problems (pretty much every garden I have ever seen), regular use of compost tea can be helpful in extending harvests of some sensitive crops, like cucumbers and tomatoes, further into the summer.
Any gardener who has a small garden, but no compost pile or worm bin at home, might be interested in trying the compost tea bags. Sustane Compost Tea Bags are convenient, and no straining is required. I have used these to make tea for my own garden, and they seem helpful. When pressed for time, it is nice to not have to strain the compost bits out of the tea before filling a spray bottle.