What ph is best for my tomatoes? I have a raised bed i've prepared well,mixing sand,clay,& organic material. I have acidifyers & neutralizers ready,but don't know which to use.Anyone to help would be appreciated.Thx
vm--common wisdom is just under 7 is best. That said, I liked the comment from well known nursery guy Carl Whitcomb that he threw away his pH meter years ago. The lesson being that the vast majority of plants do fine in quite a wide pH range as long as the soil is well drained and has adequate organic content for water and nutrient holding. Sounds like your mix could be fine, grab a handful and squeeze it and see if it seems crumbly but holds together enough...friable is a word often used. A couple things I would add, others could add or detract from this. I believe the tomato family benefits from mycorrhizae...yields from peppers and potatoes have been measurably improved, can't remember anything specifically for tomatoes. If you have a product easily available, I think it may be worth trying. This natural fungus also adjusts the pH around the plant root to optimum so pH becomes less of a consideration. The second thing I just heard about is sowing hairy vetch, a legume usually used as a "green manure", around your tomato plants. The researchers at U of Connecticut found yields more than doubled compared to bare soil between the tomato plants, plus cutting way back on potato bugs. I'm trying this myself with my greenhouse maters this season and will see how they do. So far I'm just a tad worried about the vetch climbing up and covering the tomato plants, as they grow like peas wrapping their tentacles around anything upright...so far they are very small but seem to be growing quick. I'll give my thumbs up or down on this in a few months if anybody's interested. Glen
Actually Tomatoes can handle a pH range of about 5.5 - 9.5. Of course a pH of 9.5 is extreme but I've seen it done with field grown Tomatoes around here. The leading fresh market and canning Tomato growing regions in the US all have four things in common, warm temperatures, a saline soil, lots of sunshine and ample water. I am not so sure that growing Vetch in a greenhouse will work all that well as it can easily grow out of control. For field grown Tomatoes it was not all that uncommon years ago to grow Vetch as a cover crop, then disc in or renovate the plants, let the ground stand in fallow to allow for decomposition for a few months and then plant Tomatoes. The whole purpose of a green manure crop is to add stored atmospheric Nitrogen into the soil without having to apply so much man made Nitrogen during the actual growing season. I was taught years ago that between 250-350 pounds of applied Nitrogen per acre was needed to produce a decent field crop of Tomatoes. By utilizing a green manure crop before the crop is planted we can considerably cut down on the amount of Nitrogen to be applied into the ground. That is "old hat" knowledge from yesteryear as Vetch was used as a green manure cover crop for a variety of crops here even before the turn of the 1900's. We can grow a green manure crop and an existing crop simultaneously but it is better to have ample space between the two crops otherwise they will compete with each other. With permanent fruit producing trees, nuts and Citrus we have enough space in the middles to grow a green manure crop at the same time as an existing crop but that type of double cropping is not always preferred or recommended without the green manure crop being tilled under before the onset of harvest. To allow Vetch to grow in the rows along with a Tomato crop will not work well at all for a field grown crop but for homeowners that do not mind the Vetch to invade their Tomato plants it can work. The problem will be when it comes to picking the fruit as it will be a hassle. I know, I've done it. What others do not tell you is that they will periodically mow their Vetch down that are planted in rows much wider than conventional, production Tomato row spacings, so that the Vetch will not readily invade their primary, fruit bearing crop. Jim
Jim==thanks for your thoughts re vetch in the tomatoes. My concerns are similar, that this could get to be a hassle. The researchers only said the yield more than doubled, so I can put up with some hassle if that is the payoff. Plus growing in the greenhouse up a string, the plants are more out of the way than a field crop which is usually bush style, sprawling over the ground. That would be quite the tangle of tomato:vetch by harvest time out in the field... I think the researchers were suggesting more than the nitrogen kick of a green manure crop, which could also be gained by growing the vetch the previous winter and tilling it in. There seems a possibility that the two living plants actually share nutrition between each others roots. I'm not clear what might be moving between them, but for a 120% increase in yield I'm thinking it's more than nitrogen. We could add nitrogen artificially and get a similar response if that was what "doubled" the yield. I dunno. It seems like a fun thing to try right now, if I wind up cursing this vetch a month or so from now I'll let everybody know :-) Glen
Hi Glen: I have not found the study you are referring to. I will say that Potassium is more important for Tomato yields than Nitrogen is. Too much Nitrogen and we may see lots of growth but at the expense of a noticeable lessening of flowers to set for us. The field studies I know about all pretty much used Hairy Vetch as a cover crop rather than a companion plant or a living mulch for the Tomatoes. Jim
Dear Glen: I am a home gardener and am interested in your experiment with using hairy vetch around tomato plants to improve yields (see qouted email below). Did this work? Would spreading nitrogen on the garden work just as well? Thanks in advance, Phil
Phil--with my greenhouse tomatoes in full production now, I should be able to conclude something about this living vetch mulch thing. The vetch hasn't been much of a problem thankfully--it is easily pulled away from the tomato plants, most of which are trained up strings well away from the ground at this time of year. I would also say that there seems no negative effects of all these vetch plants "competing" for water and nutrients. On the other hand, without any experimental controls, I can't say for sure what improvement if any the vetch has provided. This is my first year with a greenhouse, so the excellent tomato crop is great for somebody who only gets a measurable tomato harvest about 1 year in 10 doing it out in the open in blight infested Surrey, British Columbia. The U of Connecticut did the controlled expt. thing which I did not, all I can say is that the vetch hasn't turned out to be a bad thing, and I'll do it again (maybe even with a few "control" plants next year!). Glen
