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Sunday, April 7, 2013

Fertilize Garden Plants When They are Growing

Blood meal is one form of organic nitrogen
that can be used to side dress

            Earlier in the season, around mid-March, I was encouraging you to plant your own onion transplants and grow your own onions. They are so much better tasting and I gave the readers here and on my blog some varieties to choose from. Many are available from seed and started from seed in about mid-October, the same time as you would plant garlic.

            Most people forget a very important concept in their home gardens – regular fertilizing. As plants get bigger or start producing they are taking all of these “goodies” from the soil to get bigger or start producing. I will get back to onions in a minute.
            What would happen to you if you were always giving and receiving nothing in return? Plants can’t continue to “give” without getting something in return if you expect them to be healthy and productive. So all plants as they get bigger and you harvest require fertilizer.
Plant health depends on regular fertilizer applications if you are always "taking".
"As expectations for plants increase....more inputs (water, fertilizer, time, energy)are needed."

            Fertilize your garden plants monthly when they are producing. Think about what they are taking from the soil. Was the soil enriched at the time of planting so they have plenty to “pick from” or is the soil’s nutrient reserve running low?

Ammonium sulfate granular fertilizer also known as
21-0-0 since it is all nitrogen (21%) and no phosphorus or
            The first nutrient to disappear from the soil, for a number of reasons, is nitrogen. It is very important to supplement your vegetables with some extra nitrogen monthly.

            If the plants are up and growing it is not wise to just broadcast the fertilizer (throw it out over the garden willy-nilly) or the fertilizer “salts” may burn foliage. Deposit the dry fertilizer next to each plant or dribble it along the row. This is called “side-dressing” with nitrogen.

            Why did I mention onions earlier? Because they need to be side-dressed as well and are frequently forgotten. One more side-dressing on onion and garlic and then stop as you will be harvesting in two months.

Ammonium sulfate is a crystalline source of nitrogen that
dissolves easily in water and can be applied as a granualr
or liquid by dissolving it in water. Dissolve about one tbs
in three gallons of water or apply it dry by sprinkling on
the soil lightly and watering it in
            Use your favorite source of nitrogen. If you are an organic gardener, select an organic form that you like. If you are not that fussy, then use a traditional ag-type nitrogen fertilizer like ammonium sulfate. When you side-dress, it is normally just nitrogen as it moves into the soil freely with an irrigation.

            If these are annual plants, all the other nutrient “goodies” we normally put in the soil at the time of planting.

            What makes big onions? The variety you select, improved garden soil, spacing them 4 to 6 inches apart, regular and frequent watering, weed control and side-dressing with nitrogen as they are growing and expanding. Pull or lift them when the tops fall over naturally. If you are pulling them, make sure the soil is wet when you are pulling or you will pull the tops off.

            Remember, my blog, Xtremehorticulture of the Desert, has a lot of pictures that supplement my discussions here.


  1. Not sure I agree with this advice. I think it better to mix in a scoop or two of free compost from your compost pile with each new planting of an annual in your garden. That replenishes the nutrients (micronutrients beyond NPK too) sucked out by the prior plant without the added salt from fertilizer. And the remains of the prior plant goes into the drying area next to the compost pile for recycling. For most garden crops turnover can be every 3 months, for other plants that make it through the year and keep on producing an added compost topping gets rapidly broken down via the garden's regular watering.

  2. Without making an issue of the point of successful gardening in desert soils, I want to address two issues: making a desert soil productive and making a desert soil capable of producing the highest quality/quantity possible. Desert soils can be as productive as any soil. First there are desert soils that are not problematic and there are others which are. In the Las Vegas Valley we have soils with toxic minerals (boron, chlorides, sodium) that limit or prevent production if these are not addressed. For instance, in raw desert soils in southern Nevada we can have boron levels as high as 80ppm (boron can become toxic at 1 or 2ppm depending on what you grow) and salinity levels over 100 mmhos/cm (100 dSm/m, or approximately 64,000 ppm) We first have to address issues of poor production that might exist. We amend the soil to try to compensate for high boron content (high organic matter tends to tie up boron as long as it is not too high) or leach to remove salts. After this we can begin to address the low organic matter content and the benefits that OM provides. We want to get it to at least 5% OM starting with LV soils at .01% OM. This will not be true of desert soils that have been under production and reclaimed as urban soils. They will start with an already high (compared to .01% OM)OM content and low toxicity levels of boron, chlorides or sodium (they would not be productive in the first place if these existed at high levels). These formerly productive desert soils will not need alot to get them productive. They already are. However, the difference between productive and highly productive soils (this depends on the market you are trying to reach) will be in the "inputs" going into these soils. These inputs include sunlight, water, air/carbon dioxide, fertilizer and reduction of stresses (disease, insects, weeds). As we know, production increases to a maximum as inputs increase (these maximums and levels of inputs are different depending on what we are producing/marketing). If we look at the former Soviet Union, they were constantly trying to reach maximum output without regard for profits. Their maximum is different from the US maximum which focused on profits. The US would constantly underproduce what the Soviet system would because we maximized profits, not production. In the same regard, amending the soils at planting time is imperative and you will produce well if you do JUST this. But if you want to maximize your production (quality or quantity) you frequently will have to supplement with nitrogen in the organic or inorganic form (your choice) to reach a maximum. Should you try to always maximize production? Not if you are a capitalist. Your level of production (quality or quantity) depends on your market. Markets dictate levels of inputs in production.

    1. While quite true, I see that neither poor ORIGINAL soil condition, nor starting organic material is present in your original post. Instead it is about the need to replace (I suppose at least annually) nutrients removed by the prior growing plant before reseeding/transplanting that spot in a already productive garden.

      I am fairly confidant my finished known content compost suggestion meets ALL criterion without the fear of burning or adding salt. It certainly isn't as fast operating as ammonium sulfate or even blood meal, but it hangs around a lot longer releasing its available nitrogen in amounts less likely to be washed out or in amounts overly abundant in the beginning. Plus compost is added only in the spot(s) being planted and at the time of each planting which may be up to four times a year depending upon the plant.

      As far as capitalism goes, I will take relatively free over helping the garden industry with their $urplu$ any day. Works out better for $elfi$h old me. And among the ways of maximizing production is to minimize waste and lower the cost of manufacture which lowers "price"---even if the producer is the consumer.