We’ve been getting quite a few calls lately with growers asking if starter or pop-up fertilizer is essential for cotton, or if it can be cut out of the budget. This is a relatively common question, especially when times are tight. During flush times, we see starters commonly used in cotton and we usually dont argue with it as long as two conditions are met:

1. We dont argue with it, as long as it is not applied infurrow, but is rather applied in a true 2×2 manner, and in acceptable volumes (10-15 gal/A) so that starter does not migrate or splash into the furrow. Starters applied infurrow are always a risk. There are many cases where there is no impact on seed or seedlings. Loosely speaking, in the large majority of situations, a grower can get away with it and observe no adverse effects from starter applied infurrow. In some cases, however, the impact is substantial and stands are drastically reduced as seedlings can be killed when environmental conditions align to cause ammoniafication or salt injury. There is no recourse when this happens, and it is usually aggravating to replant when this occurs. Replanting costs can be substantial, therefore growers are encouraged to ask themselves if it is really worth the risk of applying starters infurrow given that the benefits of such are seldom to none. There are several formulations that claim to be low ammonia or low salt which brings us to our next point.
2. We dont argue with it as long as the starter formulation is an affordable way of applying a small fraction of nutrients. Another way of saying this is that we dont argue with it as long as the cost per lb of actual nutrient applied is comparable to other common sources of fertilizer. Growers are encouraged to closely consider the cost per actual lb of nutrient in starter sources.

In lean times, such as what we are experiencing now, the questions often turn to “is starter essential for cotton?”, “do I need to apply starter?”, or “is starter one of those line items that I can cut out?”. The primary advantages to applying starter include:

1. if phosphorous is needed as indicated by soil test results. In many cases, starters can be an affordable way to meet P needs. But also, most of our soils have adequate P levels. Therefore, this decision should be based on soil test results.
2. Starter fertilizer can be an affordable way to apply a small fraction of nutrients to the crop when there is essentially little to no residual N in the soil. In these cases, theoretically, starters can potentially buy you a little time if you are late when side-dressing or top dressing, but not much. As mentioned earlier, the cost per actual lb of nutrient needs to be comparable to other common fertilizer sources. If cotton is following soybean or peanut, or if we havent had substantial rainfall since the last crop season, chances are that there is some residual N remaining in the soil, at least enough to get cotton up and growing. It is important to remember that cotton utilizes very little N between planting and first square, and therefore the response to fertilizers during this period is low to none. Nitrogen uptake drastically increases once squaring begins, therefore you would want some fertilizer in soil solution once squaring begins. Therefore, if starter is not used, we need to be applying top-dress or side-dress fertilizer in a timely manner when squaring begins.
3. Starter fertilizer can occasionally result in a small boost in seedling vigor. In theory, this could help us in some regards. However, we are unaware of any replicated data anywhere (in NC or any other cotton state) that suggests that there is a yield response to starter fertilizers. In most cases, temperatures are either ideal, or too cool during planting, and no difference is observed in seedling vigor when starter is used or not. In some rare cases, we do see a small boost in vigor associated with starters, but it does not seem to translate into any benefit beyond that, such as higher yields.

Given that the benefits of using starters in cotton are seldom, or small at best, this could easily be something that could be cut from the budget. Growers are encouraged to consider all of the points made in this article when making this decision. If starter is to be cut from the budget, be timely with side-dress or top-dress fertilizer as soon as squaring begins (6-7 leaf cotton) or maybe slightly earlier than normal.