Because it had not rained, and providence in the process of creation?

וְכֹ֣ל שִׂ֣יחַ הַשָּׂדֶ֗ה טֶ֚רֶם יִֽהְיֶ֣ה בָאָ֔רֶץ וְכָל־עֵ֥שֶׂב הַשָּׂדֶ֖ה טֶ֣רֶם יִצְמָ֑ח כִּי֩ לֹ֙א הִמְטִ֜יר יְהוָ֤ה אֱלֹהִים֙ עַל־הָאָ֔רֶץ וְאָדָ֣ם אַ֔יִן לַֽעֲבֹ֖ד אֶת־הָֽאֲדָמָֽה׃ וְאֵ֖ד יַֽעֲלֶ֣ה מִן־הָאָ֑רֶץ וְהִשְׁקָ֖ה אֶֽת־כָּל־פְּנֵֽי־הָֽאֲדָמָֽה׃ (Gen 2:5-6)

In their contribution to the book The Genesis Debate: Three Views on the Days of Creation (ed. David G. Hagopian; Mission Vejo, CA: Crux Press, 2001), Lee Irons with Meredith G. Kline presented and defended the Framework view of the creation account so aptly they virtually demolished the opposition. One of their arguments which was left unanswered (in the book Ligon Duncan and David Hall tried but their response was garbled c.f. p. 261) was the argument from Gen. 2:5-6. They appealed to Gen. 2: 5-6 to establish the "principle of continuity between the mode of providence during and after the creation period" (p. 229). Since there is a such a principle of continuity, therefore ordinary providence as opposed to extraordinary providence must be operative during the creation "days." It is noted here that the topic here is providence, not miracles. The divine fiats are miracles, but the maintaining of the "stuff" already present is providence.

This principle of continuity is explained by Irons with Kline slightly later:

If our [Irons' and Kline's] exegesis of Genesis 2:5-6 is correct, then it informs us that the Creator did not originate plant life on the earth before He has prepared an environment in which He might preserve it without bypassing secondary means and without having recourse to extraordinary means. As such, Genesis 2:5 contains an "unargued presupposition," namely, "that the divine providence was operating during the creation period through processes which any reader would recognize as normal in the natural world of his day." If God had so decreed, there would have no obstacle to His creating the vegetation prior to establishing a normal providential support system. He could have created the plants and sustained them supernaturally even before He created the soil. God in His omnipotent creative power could have done these things. Yet Genesis 2: 5-6 tells us that in planning the order in which He would call the various creatures into existence, God did not rely upon supernatural means to maintain them once created. (p. 231. Emphasis original)

Since Irons and Kline see the creation account in Genesis 2 as essentially a recapitulation of Genesis 1, the statement about the vegetation in Genesis 2:5-6 is also a statement about the creation of vegetation in "Day 3" of Genesis 1, and then this "principle of continuity" is extended from plants (vegetation) to all the other aspects of creation.

In response, we need to ask why we think that Genesis 2:5-6 refer back to the "Day 3" event. We note here the object is not just vegetation in general as in Day 3 (דֶּ֔שֶׁא , עֵ֚שֶׂב - Gen. 1:11), but specifically the "shrub of the field" (שִׂ֣יחַ הַשָּׂדֶ֗ה), or "herb of the field" (עֵ֥שֶׂב הַשָּׂדֶ֖ה). While differences in words used do not necessarily imply a difference in meaning, here the adjectival phrase "of the field" seem to suggest a qualitative difference between what is discussed in Genesis 2:5-6, and what is discussed in Genesis 1: 11-12. If we discount the framework interpretation and see Genesis 2 as an expansion of Day 6 of the Creation week, then it is clear that the context, as Irons and Kline have pointed out, is for the cultivation of crops by Man. In other words, these shrubs and herbs of the fields are cultivated plants, as opposed to the generic vegetation of Day 3. It is a different episode altogether from "Day 3" but rather focuses on the Day 6 planting of Eden as the background for the creation of Man.

Once we see the events in Genesis 2 this way, then Irons' and Kline's point here falls apart. Since Genesis 2:5-6 does not pertain to "Day 3" of creation, therefore it says nothing about that episode, including the "principle of continuity." The Day 6 creating of ordinary means for watering for the cultivated plants and so on was due to the fact that Man must live by ordinary providence in his everyday life. Thus, this "principle" applies only when Man comes into the picture in Day 6, not prior to that.

Irons' and Kline's case here for the Framework view falls apart. In fact, that principle is actually question begging. For only if one holds to the Framework view can one claim that Genesis 2:5-6 to be a recapitulation of "Day 3" of creation, and only if one sees recapitulation will one argue for the "principle" which in turn proves the Framework view. When one actually looks at the details however, the supposed recapitulation however doesn't hold up.